This article on beet curly top virus in cannabis plants is largely based on the invaluable contributions of Whitney Cranshaw. Cranshaw has built an extensive repository on hemp pests (note: hemp and high-THC cannabis are the same species of plant, and experience the same pests) and generously offers pest pictures and information to the cannabis-growing and scientific communities.

I would also like to thank Dr. Punya Nachappa, Judith Chiginsky, and Bob Hammon for contributing online resources on beet curly top virus in cannabis plants to help create a comprehensive information sheet [PDF] on the subject. For further reading, Colorado State University offers more excellent cannabis pest information sheets.

Pictures of Cannabis Plants with Beet Curly Top Virus

Some cannabis plants get yellow and stunted, but may not show the “curly top” symptoms. First, the “curly top” everyone’s talking about:

“Leaf curling associated with infection of hemp by beet curly top virus.” ~Whitney Cranshaw

“‘Classic’ symptoms of beet curly top virus infection of hemp, with generalized yellowing of the plant, without leaf distortion, and stunting.” ~ Whitney Cranshaw

Leafhoppers Spread Beet Curly Top Virus!

Check out the full page on leafhoppers (one of the leading vectors for beet curly top virus in cannabis plants).

The beet leafhopper is a host for Beet Curly Top Virus, and easily spreads the disease while feeding. Photographer: A.C. Magyarosy

It is possible other types of leafhoppers, or other insects, could be spreading the virus among marijuana plants, though more information is needed.

What is Beet Curly Top Virus and How Does it Infect Cannabis Plants?

Beet Curly Top Virus (BCTV) is a cannabis plant disease that is transmitted by the beet leafhopper (Neoaliturus tenellus) and possibly other forms of transmission (other bugs, transferring the virus from one plant to another during handling, etc).

Beet Curly Top Virus (BCTV) can infect a wide variety of host plants, including sugar beets, tomatoes, beans, spinach, and cannabis (hemp) plants. I heard about beet curly top virus at the Cannabis Business Conference in 2022, though it initially was identified in cannabis plants in 2020 or earlier.

“Beet curly top virus infection showing both yellowing and strong leaf curling.” ~Whitney Cranshaw

“Closer view of a hemp shoot exhibiting leaf curling and twisting due to Beet curly top virus” Credit: pnwhandbooks.org

How the Virus Spreads to Cannabis Plants

Most commonly, the disease is spread through leafhoppers (a common cannabis pest), which feed on infected plants and then spread the virus to a clean plant on its next feeding.

So far, the Worland (BCTV-Wor) and Colorado (BCTV-CO) strains of the beet curly top virus have been identified in Colorado, but there are likely other strains affecting cannabis plants in different parts of the world.

Symptoms of Beet Curly Top Virus in Cannabis Plants

BCTV can cause a wide variety of symptoms, though the curling of new growth (“curly tops”) is the most striking.

• Twisting of new growth (“curly tops”) – New growth on the plant may display a strong twisting or curling pattern. This new growth may remain green or turn yellow. Leaves tend to curl upwards
• Stunted size – Slow growth is common, and plants may stay small or act like “runts” even if they don’t show other symptoms.
• Leaf yellowing or mottling – Early stages of infection may produce light yellowing or mottling, mostly at the base of a leaf. Over time, this yellowing may become more pronounced and eventually whole plays may become pale yellow and stunted
• Localized symptoms – Some plants may only have symptoms on certain spots, while the rest of the growth appears normal. For instance, the original stem might develop curly top symptoms, while side branches that develop later have typical growth patterns.

The total effects (overall health, yield, and other potential issues) of beet curly top virus on cannabis plants are still not fully understood, because the virus’ ability to affect cannabis plants was discovered relatively recently.

Some hemp or cannabis plants infected with the virus can outgrow most of these symptoms, but it’s still a good idea to get rid of them anyway to prevent future transmission. We need to do more research to discover all the strains affecting cannabis, and how they differ from each other.

“‘Bisymptomatic’ hemp plant infected with beet curly top. In this condition, the original plant stem shows strong symptoms of infection, including yellowing and leaf distortion. On the same plant, side shoots develop that appear symptom free.” ~Whitney Cranshaw.

How to Treat Beet Curly Top Virus (Prevention)

Unfortunately, because there is no cure for beet curly top virus, the best thing for a cannabis grower to do is get rid of all cannabis plants known to be infected by BCTV.

Note: It is possible to use plant tissue culture to grow a clone of the infected plant (typically done in a lab by experts), which gives you a clean uninfected plant with the same genetics. However, there is no way to cure a plant that already has the virus. Even if it outgrows its symptoms (which occasionally happens), it will still be able to infect other plants. Therefore it’s highly recommended to carefully dispose of infected plants.

1. Carefully get rid of infected plants – If you suspect your plant has beet curly top virus, separate it immediately from your other plants, and consider throwing it away to prevent the potential spread of the virus to other plants.
2. Get rid of leafhoppers (if any) – If you suspect your cannabis got infected due to leafhoppers, then a preventative step is to control the local leafhopper population.
3. Clean entire grow area – Outdoors, clean the area around the plants (rake up any leaves, treat for bugs, etc.). Indoors, it’s a good idea to sterilize any part of the grow space that may have touched infected plant matter.
4. Take care when touching plants – Until you’re during the virus is gone, take extra care whenever you’re touching one plant and then another. For example, if you’re defoliating or cutting off parts of the plant, make sure to change gloves before you start on another plant. You don’t want the juices from the inside of one plant to touch the inside of another plant.
5. Start with seeds – Clones will typically carry the virus if the parent plant was infected, but cannabis plants grown from seeds are rarely infected (even if their parents were). Dip seeds briefly in a 10% hydrogen peroxide solution before germination to ensure the virus is not on the seed coat. This doesn’t prevent the plant from catching the virus later, but starting with seeds helps give you a small amount of protection because, without any infected plants around, transmission is impossible.

Protect your cannabis plants from viruses so they can focus on producing amazing buds.

Conclusion

In this tutorial, we’ve unearthed vital insights about the Beet Curly Top Virus (BCTV) and its bearing on cannabis plants. From its varied host plants to its symptoms and strains, BCTV is a formidable threat that requires keen observation and swift action.

Key takeaways for cannabis growers

• Understand the Virus – BCTV is a disease transmitted to cannabis plants by beet leafhoppers and possibly other means. Simply being aware of this and its many host plants prepares you to intervene swiftly when the first signs of infection appear.
• Spot the Symptoms – Identifying the symptoms of BCTV is crucial for early detection. Curling of new growth, stunted growth, leaf mottling or yellowing, and localized symptoms are key indicators of potential infection.
• Transmission – The primary transmission method is through leafhoppers or other mechanical damage (like pruning first an infected plant and then a healthy one without washing your hands between). Understanding how transmission works can guide you toward effective control measures, like carefully handling plants and managing leafhopper populations.
• Management and Control –  Although there is no cure for BCTV, there are practical strategies for managing an outbreak. Disposing of infected plants, eradicating leafhoppers, thoroughly cleaning the grow area, and minimizing plant-to-plant contact can help curb the spread of the virus. If you’re concerned your current stock of genetics may have the virus, start your next grow with known clean plants (or seeds) to help ensure you have clean stock.

Remember, the best defense against BCTV is a strong offense. Stay vigilant, act quickly, and employ these strategies to safeguard healthy cannabis plants and yield. The journey to understanding and managing BCTV is ongoing, and your proactive efforts are a critical part of that process.

If you have pictures, information, or experience with beef curly top virus in cannabis plants, please don’t hesitate to contact us so we can help share the word!

The post Beet Curly Top Virus appeared first on Grow Weed Easy.

Cannabis Copper Deficiency Symptoms

• Leaves turn dark with blue or purple undertones
• Tips and edges of leaves turn bright yellow or white
• Shiny or metallic sheen on leaves
• Leaves may feel stiff and start turning under
• Tends to affect leaves directly under the light
• Buds do not ripen, or grow very slowly

The pale tips of a cannabis copper deficiency look a little different from nutrient burn, which may start out with slighly yellow tips, but soon makes tips appear brown or burnt.

This is what the yellow leaf tips of a cannabis copper deficiency looks like. The most telling feature of a copper deficiency is that the rest of the leaf darkens and takes on a blue or purple cast which makes the yellow tips look bright in comparison. The leaves also often appear shiny and may feel stiff.

Some strains are prone to copper deficiencies in the flowering stage, which can create dark purple or reddish hues in the leaves directly under the lights. The following picture shows a Blue Widow plant where all the leaves under the light turned purple due to too-bright light and incorrect pH triggering a copper deficiency.

A cannabis copper deficiency tends to affect the leaves directly under the light. If your grow light is close it may help to move lights a little further away.

A big problem with a major copper deficiency if it happens early in the flowering stage, is the affected leaves are not good at photosynthesis and won’t provide nearly as much energy for the buds as they would if they were green. It’s important to keep leaves near the buds healthy during the majority of the flowering stage to help ensure you get the best yields possible. While it’s normal for leaves to start dying in the last week or two before harvest, you should react quickly if you’re seeing unhealthy leaves earlier than that!

It is very unlikely that there is no copper available in your water or soil, so usually a copper deficiency in cannabis is caused by a pH problem at the roots that is restricting access to nutrients.

Copper toxicity (too much copper) in cannabis plants is rare, though a severe case of too much copper can cause a quick death to the plant.

Solution For Cannabis Copper Deficiency

1.) Adjust pH to Correct Range

The most common reason growers will see copper marijuana deficiencies is when the pH at the roots is not in the correct range. Copper tends to get locked at certain pH levels, and is better absorbed by the plant in a slightly acidic root environment.

If you suspect your growing cannabis plant has a copper deficiency due to incorrect pH, flush your system with clean, pH’d water that contains a regular dose of cannabis-friendly nutrients. This will remove any nutrient salts that may be affected the uptake of copper and help restore pH to the proper levels..

Watch to make sure that the problem starts to clear up within a couple of days. Old growth may not recover, but new growth should be healthy.

• In soil, copper is best absorbed by the roots in the 6.0 – 7.0 pH range
• In hydro, copper is best absorbed by the roots in the 5.5 – 6.5 pH range

Learn how to manage your pH for growing cannabis.

2.) Give the Right Nutrients

The truth is, most cannabis growers don’t need to add more copper in response to a copper deficiency!

In fact, most growers have actually already given plenty of copper to their cannabis plants since it is found abundantly in most tap water. If you’re using quality soil or cannabis-friendly nutrients, you probably don’t need to worry about adding more copper. In general, copper deficiencies are more likely to appear when a grower is using heavily filtered or reverse osmisis (RO) water to feed plants since any copper has been removed, but pH is a much more common reason growers see copper deficiencies in their cannabis plants.

3.) Take Good Care of the Roots

Copper deficiencies can show up with the plant is having root problems or if the plant is overwatered, even if the pH is right and the copper is there. Proper watering practices help plants grow healthy and avoid a host of problems!

4.) Watch for Leaf Recovery

After going through all the above steps, watch to make sure that the copper deficiency starts to clear up within a few days to a week or so. The damaged leaves may not completely recover all their green, but you know you’re in the clear when you stop seeing symptoms appearing on new leaves.

If you cannot get rid of a cannabis copper deficiency, please consult our 7-Step Cure to 99% of Cannabis Growing Problems with chart!

The post Copper Deficiency appeared first on Grow Weed Easy.

Do Your Marijuana Leaves Have Nutrient Burn?

Quick Summary: Nutrient burn or fertilizer burn is one of the most common beginner cannabis growing problems. The yellow or brown leaf tips are caused by too-high levels of nutrients at the roots, which disrupts the flow of water through the plant and causes the symptom of burnt tips on leaves.

(Nutrient burn is often called “Nute Burn” in the cannabis growing community).

“Nutrient burn” causes cannabis leaf tips to turn brown and crispy.

When the roots take in more nutrients than a cannabis plant can use, the overabundance causes problem with water flow in the plant, triggering brown or bronze “burns” on the tips of your leaves. If nutrient levels are not lowered, the burnt tips start traveling inwards and the ends of leaves start becoming crispy and twisted.

Take me straight to the solution for cannabis nute burn!

As nutrient burn progresses, the tips start getting bronze, crispy, curled and sometimes twisted. Although you can stop nutrient burn from getting worse, the burnt appearance won’t go away on the leaves that were already affected.

Nutrient burn is most common when feeding cannabis too-high levels of bottled nutrients and especially chemical or mineral nutrients. This is what you’ll find in most non-organic plant food.

Mineral-based nutrients can help increase cannabis growth rates and yields compared to organic-based nutrients due to the fact that these nutrients are so easily absorbed by the plant roots. The plant doesn’t have to do any “work” to get the nutrients. The downside is your plant can easily take in more than it can use if the nutrient levels are too high.

Nutrient burn affects the tips of marijuana leaves. You may just see it on one or two leaves, or it can appear all over the plant.

Nutrient burn can also happen when plants or seedlings are grown directly in soil that has a high level of nutrients (a “hot” soil or growing medium) such as fresh compost, manure or a nutrient-amended soil mix. This usually happens to young seedlings, and they will “grow out of it” as they begin to use up all the nutrients in the soil, as long as more nutrients are not added.

In general, plants use overall higher levels of nutrients as they get more light. Therefore plants in relatively low light conditions can get nutrient burn at lower levels of nutrient than the same plant would under bigger grow lights.

Each cannabis plant is different, so you might have just one out of many plants get nutrient burn! That is completely normal.

Sometimes you’ll also see nutrient burn leaf tips also curl or “claw”. The clawing can be caused by an overabundance of Nitrogen (Nitrogen Toxicity), which is common for plants that are experiencing nutrient burn from overall high levels of nutrients.

Problem: You will notice the tips of your marijuana leaves showing the first signs of nutrient burn by turning yellow, tan, gold or brown. A light case of nutrient burn will only affect the tips of your leaves.

The yellow tips will eventually turn rusty brown and crispy. If you do not correct the problem, you may also notice the burn slowly spreading from the tips to the whole leaf. At this point, if you haven’t done so already, you should immediately treat your plant (directions below) before there’s more damage.

Nutrient burn can also manifest itself as brown or bronze spotting around the edges of the leaf serrations (often when there’s a problem with proper absorption of potassium), or with leaf tips curling downwards (tips pointing down is often associated with too much nitrogen).

Nutrient burn causes tips to start curling up if it gets bad enough

These Are NOT Nutrient Burn!

(Sometimes Mistaken for Nutrient Burn)

Light Stress can cause yellow tips or edges, which can sometimes be confused with nutrient burn

This is actually a Potassium Deficiency, not nutrient burn!

pH Fluctuations

See more examples: Is this actually nutrient burn or something else?

Why Growers Should Try to Prevent Marijuana From Getting Nutrient Burn

I have heard some growers say that a little nutrient burn is actually a good thing, because it means that you are giving your plant the highest level of nutrients it can use. A lot of growers have the mistaken idea that nutrients are somehow “food” for your cannabis plants, and so more food = more energy = bigger yields.

This is wrong, instead nutrients are more like a multi-vitamin for your plant. Just like you can’t give a child 10 multivitamins a day to make them grow faster, you can’t give your plants 10x the regular does of nutrients and expect anything good to happen.

The real “food” for your plant is light. Your plant produces energy from light through a process known as photosynthesis, which is most effective when the plant has healthy green leaves.

Learn what yields to expect based on the type of grow light you have!

Your leaves are like solar panels, and the energy produced by the leaves is used as energy for the whole plant. You need the leaves to be in tip-top shape to get the most energy from the lights, so your plant has plenty of energy to grow and produce buds.

Therefore, the biggest problem with nutrient burn is the fact that you are losing leaf mass and overall leaf robustness on your cannabis plant.

A little nute burn won’t slow down your plants much, if at all, but if nute burn is left out of control, you will begin to lose serious leaf mass and it will dramatically slow down plant growth and reduce your overall yields.

What’s worse, if excess nutrients are not flushed out of the plant’s system before harvest, the buds may contain trace amounts of extra nutrients, giving the buds an unpleasant chemical-like taste. Speaking of the flowering stage… (Wait, what’s the flowering stage?)

Nutrient Burn is More Serious in the Flowering Stage

Cannabis plants spend the beginning part of their life in the vegetative stage. When cannabis plants enter the second part of their life, the flowering stage, they stop focusing on making leaves and stems, and put all their focus on making buds/flowers.

The flowering stage is the most vulnerable stage for cannabis plants, because they don’t have much ability to bounce back from any problems.

The further you get into the flowering stage (and the closer you get to harvest), the less likely the plant will replace a leaf that is damaged or dies. By the time harvest is around the corner, your plant basically stops making any effort to recover from leaf damage, and its complete focus is on fattening buds.

That’s why budding cannabis plants need extra care to thrive – in the flowering stage, a little bit of nutrient burn will probably be okay, but too much nutrient burn can seriously hurt yields because the plant will not be able to recover. If you are adding nutrients to your water, it can be very easy to burn your plants in the flowering stage (even with nutrient levels it was fine with before) as different strains have different needs throughout budding.

Solution to Cannabis Nute Burn

If you are using bottled nutrients – Most people who get nute burn are feeding their plants extra nutrients in the water. First off, make sure you are using a quality set of nutrients that has been specifically designed for cannabis plants. Any nutrient system designed for plants like a tomato will also work in a pinch. Also make sure you are feeding nutrients for the right growth stage – for example, all cannabis nutrient systems have you feed different nutrients for the vegetative and flowering stage. If you are feeding the wrong type of nutrients for the stage your plant is in, that is an easy way to give your plants lots of nutrient problems including nutrient burn.

If you are using the wrong type of nutrients for a plant like cannabis, you will eventually run into nutrient problems, one way or another.

Many nutrient systems come with instructions to feed your plant more nutrients than most plants actually need. It’s good business for the nutrient companies if you use more nutrients. However, in my experience it’s a good idea to view the feeding charts that come with any nutrient system as the maximum amount of nutrients and actually start with much lower levels. I tend to start with half the recommended amount, and slowly work my way up only if needed.

Hand-watered system – If you are growing in a hand watered system (like in soil or coco coir), flush your system with plain, pH’ed water if you notice the first signs of nutrient burn. (Learn about pH). If you are not adding any extra nutrients in your grow, then you simply need to wait until the plant uses all the excess nutrients in the soil – after the nutes have been used up, the plant will naturally get over the nute burn (old leaves won’t recover, but leaves should no longer be getting new brown or burnt tips).

Hydro system – Reduce the overall levels of nutrients in your water reservoir by either adding plain pH’ed water to dilute the water, or you could also mix up a new set of nutrients (at lower levels) and completely change the water.

Be careful not to make big changes too fast, it’s better to go relatively slowly in hydro.

In hydro, once you change the water and lower the nutrient levels to an appropriate level, you should immediately notice the nutrient burn stop spreading. Old leaves won’t recover, but you shouldn’t notice any leaves getting worse.

If you don’t have a TDS meter to measure the levels of nutrients (and other extra stuff) in your water, I would normally start your plants with a fraction (perhaps 1/2) of the nutrients you were giving them before – and then work your way up to higher nutrient levels only if you notice the lower leaves are starting to yellow too quickly (nitrogen deficiency). Even then, try to move up nutrient levels as slowly as you can. If you lose leaves to a nitrogen deficiency from slightly too-low nutrient levels, you will lose a few of the least important lower leaves. But if you raise nutrient levels to fast and get nutrient burn, all the leaves on the whole plant will be affected and never recover fully.

One of the things that can be frustrating about hydro is that different plants or strains will be okay with different amounts of nutrients. You can be giving 2 plants the exact same levels of nutrients, and one might get nutrient burn while the other plant is getting a deficiency at the same level. This is because different plants absorb the nutrients at different rates.

Plus, plants drink more or less water depending on the temperature and humidity of your grow area, so even if you’re familiar with the nutrient levels of a particular strain, it can be hard to keep track of the exact right nutrient levels until you get familiar with your setup, unless…

Luckily, there is an awesome tool to make this much easier in hydro.

In hydro, it is very helpful to get a tool called a TDS meter to help you regulate the amount of nutrients in your water. A TDS meter will be able to tell you how much “stuff” is in the water, and whether the levels of nutrients are getting higher or lower each time you check. You can test your reservoir at any time to see if the levels of nutrients are rising, so you’ll be able to stop nutrient burn before it even affects your plants.

I use the HM Digital TDS-3 meter.

To find out more about using a TDS meter to measure nutrients in your water, check out our article: PPM: What It Is and How To Track It.

Could your cannabis also be suffering from Nitrogen Toxicity? – Nitrogen toxicity is common on cannabis plants with nutrient burn

Are the ends of leaves curling like a claw or pointing down like talons? If your plant is experiencing “the claw” and not just normal drooping like from underwatering or overwatering, then you may have a nitrogen toxicity (too much nitrogen).

These Plants Are NOT Overwatered, These Leaves Show Signs of Nitrogen Toxicity

Learn more: Nitrogen Toxicity
(“The Claw”, tips bent down, curling / clawing, dark green leaves)

Nitrogen toxicity is relatively common with plants experiencing nutrient burn.

The post Nutrient Burn appeared first on Grow Weed Easy.

Table of Contents

Introduction to Root Rot (With Tons of Pictures!)

What Triggers Root Rot?

Solution: Get Rid of Root Rot Forever!

Cannabis Root Rot – Slimy, brown, twisted or unhealthy roots are caused by unwanted pathogens in your hydroponic tank!

The marijuana plant on the left is healthy, and the plant on the right has root rot. The curled, drooping, unhealthy leaves are the result of the plant not being able to get enough oxygen through the roots. Root rot symptoms often look like a soil plant that has been severely over or under-watered.

Go Straight to the Solutions for Root Rot!

An example of what cannabis root rot can look like “under the hood”. Every infection looks a little different, but brown roots are usually the main symptom. It may affect all or just parts of the roots, and the sick sections usually become slimy or mushy and start twisting together.

Healthy Cannabis Roots Are White or Cream Colored!

Check out a quick Youtube video showing what a cannabis seedling with root rot looks like.

Root rot can be caused by several different organisms including types of bacteria, fungi, algae and parasitic oomycotes. Although the symptoms are similar between different types, they don’t always look exactly the same. However, growers generally refer to all types of unhealthy root browning as just “root rot.”

Root Rot causes droopiness and other symptoms similar to over or under-watering

Common Triggers for Root Rot: Light Leaks, Heat, & Lack of Oxygen in the Water

Because cannabis root rot can be caused by different pathogens, a solution that solves the symptoms of root rot for one grower may not necessarily work for another grower. What’s attacking your roots in California might be completely different from what’s attacking the roots of a grower in Australia. That being said, there are tools to fight against root rot no matter what kind you have!

The first sign of root root is usually a brown tinge on the roots.

Some varieties of root rot mostly affect the roots below the surface of the water while the roots located above the waterline stay white and healthy. This phenomenon is part of why it’s often recommended that hydro growers maintain at least a small amount of air gap under the net pots. Oxygen-rich moist environments (including that misty air gap) make it very difficult for root pathogens to grow.

Sometimes even the roots above the waterline appear brown. The white strands you see in this picture are actually new roots coming out of the old unhealthy stuff. When new white roots are growing, it’s a sign the plant may be getting better! Even after roots have recovered, you may see the brown for a while until it’s completely covered by new white roots again.

Brown, infected cannabis roots often appear twisted. In fact, sometimes them getting twisted up after being moved around by the grower is what triggers root rot in the first place.

If cannabis roots get twisted due to handling, it can trigger the roots below the “twist” to die.

Sometimes the twisting/bunching together is actually the result of the infection. Healthy roots have individual “strands” that tend to stay separated even when they’re all floating together in a reservoir.

Sometimes the infection hits first, and roots start twisting as a result of the root rot.

A mass of root rot. The grower believes the main cause was that the water level in the reservoir was too high.

Depending on what pathogen in particular is attacking your marijuana roots, the symptoms may look different.

Cannabis roots with root rot sometimes look mushy or slimy and can almost look like they’re covered in snot 🙁

This case of root rot was caused by a brown algae bloom. Brown or green algae is especially common in hot temperatures or when there are light leaks!

Algae started growing from light getting into the reservoir.

Important: The Following Roots Are Stained from Nutrients – They Are NOT Brown from Root Rot

Nutrient-stained roots are not slimy or smelly and all the roots are evenly dyed the same color. You’ll be able to see each individual “strand” on healthy cannabis roots, as they won’t be twisted together. You also won’t see leaf symptoms or wilting on the plant itself.

The first sign of root rot is usually wilting or drooping, though sometimes you won’t have any symptoms at first. Root rot often strikes immediately after disturbing the roots or completing a reservoir change, especially with young plants. It’s a good idea to avoid disturbing young seedling roots when possible! This gives roots time to build up a biofilm that protects them against root rot.

Learn how to care for hydroponic cannabis seedlings!

This cannabis plant was completely healthy the day before, but started looking weak after being transferred from one hydroponic reservoir to a different one. The thin, light colored plastic of the reservoir may have been letting light through, making the reservoir a haven for root rot. Additionally, the temperature was about 85°F (30°C) in the grow space!

Cannabis root rot can cause leaf symptoms that can look like almost anything: cannabis leaves get burnt edges or tips; yellow / bronze / brown spots or stripes; nutrient deficiencies; clawing and curled edges; and other unusual leaf symptoms.

Typical signs of root problems, like unhealthy leaves, yellowing, or nutrient deficiencies, are often present.

Root rot can cause curling leaves and brown or burnt patches.

Sometimes you’ll have a plant with root rot that looks completely healthy other than the roots. Don’t ignore this problem as you will likely start getting symptoms!

What Causes Root Rot in the First Place?

The plant ailment we think of as ‘Root Rot’ is actually a bunch of similar symptoms caused by many different types of organisms. Since these organisms all cause the same problem – gross, brown roots – we group them together. In addition to these harmful organisms all causing similar symptoms, they also show up for the same reasons.

So what causes root rot? If you’re growing in soil or coco coir, there’s one main cause: stagnant water at the roots. If your plants are sitting in old water that’s getting light (from the sun or otherwise), their roots are connected to a breeding ground for unwelcome organisms.

Root rot is a major problem to look out for in DWC many factors can cause it to show up. The most common are:

• Heat – A warm reservoir makes it easier for bacteria to reproduce. In fact, keeping a cool reservoir makes for an environment in which harmful bacteria/fungi/etc. just can’t survive.
• Light leaks – Light in your reservoir equates to a population boom for some of the smaller, unwanted populations living.
• No air space – There should be a space with air between the bottom of the net pots and the top of the water reservoir, about the width of a few fingers. If the water is touching the net pot, that can increase the chance of root rot.
• Lack of oxygen in the water – When you remove the air and agitation from your reservoir water, it’s party time! A gross, smelly, sad party. Hydroponic roots need lots of bubbles full of oxygen-filled air.
• Moving young roots – Young roots need time to build up their defenses. Moving them around not only weakens them, but it potentially exposes them to new pathogens or getting twisted when put back in the water.
• Decaying matter in the reservoir – Old bits of dead leaves can be the start of something bad. Make sure you fish any plant matter out of your reservoir when you see it. Except for your roots…leave those in there.

Your cannabis plant has started drooping, leaves are getting sick, and roots are brown, twisted, smelly and/or slimy. These are all signs you have cannabis root rot 🙁

When a cannabis plant is wilting or drooping, whether it is in soil, coco or hydro, it is almost always a sign that’s something is going on at the roots.

The wilting is often soon followed by other symptoms to the leaves, especially burning, brown spots, nutrient deficiencies, spotting, and other unusual leaf symptoms.

Root rot can cause a wide range of symptoms, because without the roots the plant is shutting down!

Plants with root rot often start drinking less water. If you notice symptoms in your cannabis plant, make sure to take precautions to stop root rot from getting worse.

Some brown roots may eventually turn white again after the root rot is gone, but it’s important to note that damage is permanent on the leaves. Brown leaves will never turn green again. You need to watch the roots and the new leaf growth for signs of root rot recovery.

Root rot mostly affects marijuana plants in hydroponic systems, but roots can also get pathogens as a result of over watering your plants in soil or other medium. Basically, anytime the roots are sitting in wet conditions for too long without any oxygen, they are at risk of developing root rot.

Symptoms of Root Rot

• Droopy – Cannabis plants with root rot almost always appear overwatered or droopy (sometimes plants wilt overnight!)
• Roots seem unhealthy – Brown, slimy, or smelly roots.
• Leaf symptoms (deficiencies) – Plant leaves often start turning yellow/white or get brown patches. You may see what appears to be a random mix of nutrient deficiencies on the leaves. This is due to the fact that the plant can’t absorb nutrients properly at the roots even if they’re there
• Dying leaves – Leaves may start dying and falling off rapidly.
• Drink less – Plants may drink much less water than usual.

Now that you know what root rot looks like and how to get it, it’s time for cannabis root rot solutions!

Solution: What to Do About Marijuana Root Rot, Algae Growth & Slime in the Reservoir

It can be tough to get rid of root rot and many growers feel it’s easier to just scrap the plant and start over. However, if you’re growing in the same spot you’re likely to get it again unless you find a true solution, and there are proven techniques that will cure your plant of root rot problems!

In order to get rid of root rot successfully, you need to take a two-pronged approach. You will need to…

1. Treat the plant’s root directly with something that will help protect them against root rot
2. Change the plant’s environment so that root rot no longer has a good place to grow.

Go through the below list and make sure you’re covering all your bases to get rid of root rot permanently and prevent a re-occurrence. It’s also important to note that affected roots will likely never recover, just like how discolored leaves on the plant will never recover. What you’re looking for is new, healthy white root growth coming out of the old sick roots.

Learn how to prevent and treat cannabis root rot…

1.) Add Beneficial Root Bacteria – Crucial!

Some people (like me) add beneficial bacteria to their water to help prevent and treat root-related plant diseases and help make nutrients available to the plant. Some of the formulas available are Hydroguard, VooDoo Juice, or Great White. Most of these can be used with both hydro and soil grows.

Hydroguard (Recommended)

I personally recommend Hydroguard because I’ve used it successfully to treat root rot in hydro, and I’ve also seen it work for many other hydroponic cannabis growers, too! It’s pretty inexpensive, and concentrated enough that a single small bottle can last throughout your grow.

The “secret sauce” in Hydroguard is a specific type of bacteria called Bacillus amyloliquefaciens. It survives in hydroponic reservoirs better than other types of Bacillus bacteria and fights many root ailments including different types of fungi, bacteria, and oomycotes. It not only gets rid of and prevents root rot, but there’s some evidence Bacillus a. may actually help lower salt concentration in the plant tissue itself.

For my hydro plants, Hydroguard has proven to be the most effective root rot prevention supplement.

Great White Root Powder (If Hydroguard Doesn’t Work)

Great White is another root supplement that works by giving your plant roots lots of good stuff to help it be more resistant to root rot. Some growers (myself included) have tried Great White without seeing any root rot recovery. However, other growers have had great results with this supplement! For example, in our growing forum, just like Hydroguard, some hydroponic growers have been able to cure their root rot simply by adding Great White to their reservoir.

It all depends on exactly which organism is growing in your tank! What was growing in mine might not be the same as what’s growing in yours, so when it comes to “good bacteria” supplements it can’t hurt to try more than one if the first one doesn’t work.

A small sample of Great White doesn’t cost much, so if you’re still struggling with root rot after trying everything else, it’s worth giving it a try to see if it works for you!

Some hydro growers also swear by VooDoo Juice but we haven’t tried it ourselves for preventing root rot.

SM-90

Note: SM-90 has been temporarily discontinued. See this article for more info.

2.) Lots of Bubbles

As I mentioned, it is incredibly beneficial to try to get as much oxygen as possible dissolved in your water. Therefore, it’s a good idea to buy a medium sized air pump and big air stones for your hydroponic system.

Up to a point, the more bubbles and surface agitation, the better, as this dissolves more oxygen into the water. As long as the roots are not being very disturbed, you can’t really go wrong with adding more oxygen.

Root rot cannot thrive in an oxygen-rich environment and your plants will grow faster with lots of oxygen. I use one EcoPlus 2 Air Pump w/ 2 Outlets for each 10-gallon container (which each holds 5 gallons of water), which I have connected to 2 large air stones per air pump since this one has 2 outlets; this helps make sure there’s plenty of oxygen in the water healthy roots and faster growth.

You need 3/16-inch standard aquarium tubing to hook everything together. Try to get tubing in black if possible, to ensure light can’t get through.

Air stones disperse the bubbles into the water.

3/16″ Flexible Airline Tubing for Aquariums is the standard size to connect an air stone to your air pump.

An air pump pumps air into your reservoir through the tubing where it gets turned into bubbles.

This has worked great for me. I haven’t had root rot since I started using this air pump/air stone combination with Hydroguard. But lots of different pumps and types of air stones will work great. The important thing is to make sure that you’re seeing lots of bubbles!

3.) No Light Leaks in the Reservoir!

Your roots don’t like light, which is reason enough, but the bad organisms that attack cannabis roots love the heat and light they receive from your grow lights!

Therefore, hydro growers want it to be completely pitch black in their DWC reservoirs. You should not be able to see even a tiny bit of light where your roots are!

You don’t need to worry as much about repairing light leaks when using a dark, thick and sturdy tub as your water reservoir

I love this idea from Farmerjim420. Help block light and heat from the reservoir with a simple towel!

In order to accomplish a totally dark reservoir for your marijuana plants, here are some things to keep in mind!

1. Consider the Material & Thickness of the Reservoir Tub – Darker and thicker material will let less light through to the reservoir.
2. Consider Reflectivity – Pale colors tend to reflect back more light and heat, but you can always increase the reflectivity later by covering the lid with a reflective material!
3. Check Thoroughly for Light Leaks! You may need to get down low and look up to see them!
4. Use Opaque Tape to Cover Any Light Leaks – Electrical tape and reflective tape are great options for covering up places where light is getting through.
5. Use Dark (Light-Proof) Tubing – Another way to protect the water from light exposure
6. Light-Proof Your Net Pots. Neoprene net pot inserts are great to fill in the net pot instead of using clay pebbles, and won’t let any light get through.

All the Hydroguard, Great White, H2O2, or other root supplements in the world often won’t solve a root rot problem if there’s a light leak!

Read the Complete Tutorial on Preventing Light Leaks in a DWC Reservoir!

4.) Keep Grow Room Cool

Lower the temperature of the grow space under 80°F, and even better under 75°F.  This also lowers the temperature of the water in your reservoir. Water can’t hold much dissolved oxygen at higher temperatures and your plants need oxygen to “breathe.”

Getting more oxygen to the roots not only helps fight root rot, it makes your plants grow much faster. If it’s too hot in the grow space, you’re much more likely to run into root rot as well as overall droopiness.

In an ideal world, the maximum recommended temperature for the water in your reservoir is around 72°F (22°C) and some growers will go to great lengths to keep their reservoirs very cool. However, when using a great supplement like Hydroguard that fights root pathogens directly, you can often keep the temperature quite a few degrees higher without as a problem.

Learn how to control the temperature in the grow room

Cannabis plants like about the same temperature as humans do!

5.) Avoid Disturbing Roots, Especially Young Plants

When it comes to nutrients and plant growth in a hydroponic setup, it’s important to watch over your roots and change your reservoir water regularly. This is especially important in the flowering stage when the plant is very sensitive to nutrients and pH. Regularly changing your water every 7-10 days will help your plants get better access to nutrients, and help prevent deficiencies and toxicities.

However, when your young seedling or clone is first getting established in your hydroponic system, it doesn’t have an established a colony of good bacteria around the roots, and has not yet grown a biofilm that protects the roots against pathogens.

During this initial period, a full reservoir change can throw everything off balance, and your roots have to sort of “start over” from the beginning.

That’s why if you historically struggle with root rot, it’s recommended for the first 3-4 weeks of your cannabis plant’s life to only top off the reservoir with additional nutrient water, and hold off on a full reservoir change until your plants have grown lots of roots with a healthy layer of biofilm over all the roots and sides/bottoms of the tank.

6.) Keep Everything Extremely Clean & Sterile

In a hydroponic system, make sure that any dead roots, dead leaves or other types of plant debris doesn’t get into the reservoir because they will provide a breeding ground for bad bacteria as they start rotting. If you do notice organic matter in the reservoir, fish it out as soon as possible.

You also want to keep your grow area as clean as possible at all times to stop bacteria before it starts. Before you begin your grow, it’s a great idea to clean all grow-related items to kill any bacteria or fungus.

Hydrogen Peroxide (H2O2) Is Only a Temporary Solution: Use alongside something else for more long-lasting prevention!

Some people recommend treating cannabis root rot with H2O2, also known as hydrogen peroxide. While adding hydrogen peroxide to your water will kill most bacteria and pathogens, including the ones that cause root rot, it is only effective in your system for a day or so or since the H2O2 is quickly converted to oxygen and water.

Therefore, if you use hydrogen peroxide as a treatment for root rot, you will need to treat your water daily to prevent re-occurrences until you actually fix the problem that is causing your root rot in the first place. I have used commercial grade H2O2 against root rot more than once, and I never saw any noticeable difference, so I would NOT RECOMMEND H202 as any type of long term cure!

Why Not Use Hydrogen Peroxide? H2O2 is only temporarily effective at best when it comes to getting rid of root rot. It makes me so sad when people tell growers to use H2O2 (hydrogen peroxide) to kill root rot because I know they will continue to struggle with it. Even the commercial grade stuff just doesn’t work most of the time (and I’ve tried)!

All H2O2 does is cause bubbling near the dead brown roots (or any organic matter), which is why I think people believe it’s helping. In my experience, it doesn’t help the plants themselves (they don’t look any better), and what’s worse, all the H2O2 will be completely gone from the water within 24 hours.

H2O2 kills most of the bacteria in the reservoir, including any good bacteria you’ve added, and does nothing to address the underlying problem. You can’t sterilize away root rot, it attacks people everywhere! Although H2O2 does kill bad organisms, it leaves enough of it there to repopulate your reservoir.

I personally recommend Botanicare Hydroguard (the newer, improved version of Botanicare’s popular “Aquashield” root supplement) for marijuana root problems because I’ve used it successfully to get rid of more than once case of Root Rot (and by ‘successful’ I mean new white roots exploded out of the old mushy brown ones and I was able to eventually harvest the buds – look at the pics below).

Hydroguard (and their old supplement Aquashield) are also much cheaper than most other similar root treatments, and in my experience more effective.

Take a look at what happens with the roots from using a supplement like Hydroguard.

What you are looking for is new healthy white roots growing out of the old brown roots. Eventually, as the root ball gets bigger, you will no longer be able to see the old brown roots. After you start noticing a recovery, some growers will snip off old dead roots, but I often don’t.

Before – Roots Just Got Root Rot

Roots are beginning to recover…

Notice the new white roots growing out of the old brown dead ones within just a day or two of receiving Hydroguard in the reservoir. By this point, the plant has stopped showing any new symptoms and appears to be growing normally.

Roots are now mostly recovered below…

Notice that you can barely see any signs of the old brown, and all the new roots generally appear white and healthy. The plants on top are lush, healthy, and fast-growing, though the old burnt leaves never recovered.

In addition to treating root rot, I like to use Hydroguard or as a preventative. It is surprisingly effective even in warm reservoirs. Hydroguard have definitely gotten me through a hot summer before.

Since I first started using Hydroguard in DWC, bubbleponics, and other hydroponics, it has successfully prevented me from getting root rot as long as I keep using it. I also use it when growing in soil if I suspect root problems.

Read a case study about how another grower was able to get rid of cannabis root rot

Jump to…

Case Study: Root Rot Recovery

Other Cannabis Root Problems

Over-watering Cannabis

How to Grow Hydroponic Cannabis

Yuck! Follow This Tutorial and Never Get Root Rot Again!

The post Root Rot appeared first on Grow Weed Easy.

Leaves that turn into claws often start turning yellow and dying if the nitrogen toxicity is not treated, much like a nitrogen deficiency, only the leaves will continue to get more and more clawed. Leaves eventually turn yellow or brown and fall off. You can tell if yellowing is caused by too much nitrogen because the rest of the plant will be dark green, and the yellowing leaves will turn into claws first.

The majority of times that growers encounter problems with nitrogen, it’s from giving too much of it to their plants.

Many new growers accidentally give their plants give too much Nitrogen, especially in the flowering stage. This results in dark, shiny, clawing leaves.

​

Your plant needs a lot of nitrogen in the vegetative stage, and it’s generally hard to give too much as long as you’re not going completely overboard with nutrients. Nitrogen is a big part of what makes leaves green, and is incredibly important to the process of photosynthesis (making energy from light).

But cannabis plants need relatively low levels of Nitrogen in the second half of the flowering/budding stage. While your plants still need N (nitrogen) during flowering, too much N at this stage will prevent your plants from forming buds properly, resulting in lower yields, less potency and possibly inferior buds.

This is why it’s important to avoid any type of “time-release” nutrients or soil (for example, standard Miracle-Gro soil) as they will keep giving your plant a lot of N even after its started flowering.

When it comes to nitrogen, this is what your plant needs:

Vegetative Stage – higher levels of Nitrogen (pretty much any plant food will do)

Most complete plant foods that you get at a gardening store contain high levels of nitrogen (N). These nutrient systems tend to work well in the vegetative stage.

Some examples of cannabis-friendly one-part Vegetative nutrient systems…

• Dyna-Gro “Foliage Pro”

• General Hydroponics “FloraNova Grow”

• Pretty much any complete plant food

Flowering Stage – lower levels of Nitrogen (use “Bloom” or Cactus nutrients)

It’s extra important to find a nutrient system with lower levels of nitrogen for the last part of your plant’s life. Many “Bloom” or “Flowering” style base nutrients are just the ticket.

Some examples of good one-part Flowering nutrient systems…

• Dyna-Gro “Bloom”

• General Hydroponics “FloraNova Bloom”

• If you can’t order online and can’t find a good one-part base Bloom formula locally, you do have other choices. Though not an ideal choice, most Cactus plant foods will contain good nutrient ratios for growing cannabis during the budding stage. So in a pinch, you can use the cactus nutrients that can be found at most gardening stores.

Different strains react differently to nitrogen toxicity. Some plants get dark green leaves with no clawing. Some strains will get leaves that do the weird 90 degree bend at the tips, while other strains or individual plants start curling like claws and then turn yellow / brown and fall off like a deficiency. Yet these are all signs of too much nitrogen.

Signs of Nitrogen Toxicity

• Dark green leaves and foliage
• Leaf tips may turn down, without signs of overwatering.
• You may notice yellowing on the affected leaves or other signs of nutrient deficiencies as time goes on
• Nitrogen toxicity is often but not always accompanied by nutrient burn
• The Claw often seems random, affecting leaves here and there
• Heat and pH problems will make the clawing worse, as they stress out the plant and lower her defenses, and cause her to drink more water (and uptake more N)
• As time goes on, the claw leaves will eventually start turning yellow, getting spots, and dying

This cannabis seedling is dark because it was underwatered in a “hot” soil mix (too much Nitrogen), but after watering the plant as normal for a week or two, the plant started growing vigorously

Solution: Reduce the Nitrogen your plant is getting!

Reduce the amount of nitrogen that is being fed to the plants. If you are feeding extra nutrients, cut down that amount. If you are in the flowering / budding stage, make sure you’re using a formula that’s specifically meant for flowering, or else it could have too much nitrogen.

If you are not feeding extra nutrients, you may have “hot” soil that has been giving your plants extra nutrients. In that case, flush your plants with filtered, pH’ed water to help clear out the extra nitrogen.

Effected leaves likely won’t recover, but you should see the problem halt with no new leaves being affected.

Wait! I’m not sure if it’s Nitrogen toxicity!

The post Nitrogen Toxicity appeared first on Grow Weed Easy.

What Does a Cannabis Potassium Deficiency Look Like?

Leaf Problem / Symptoms: With a marijuana potassium deficiency, you’ll generally see symptoms on older leaves, but not always. Sometimes you’ll see the symptoms at the top of the plant. Leaves with a potassium deficiency get yellow, brown, or burnt edges and tips. The burnt edges may look a little like nutrient burn, except the affected leaves also start turning yellow in the margins.

Example of a marijuana potassium deficiency with common leaf symptoms

You may see the brown burnt edges first, or you may see the yellowing first. When the leaf symptoms are both present, it’s a good sign you have a potassium deficiency in your leaves.

Plants may stretch and stems may become weak, but leaf symptoms are more noticeable. The leaf symptoms appear somewhat similar to an iron deficiency in that they can turn bright yellow, but the tips of the leaves curl as the edges turn brown, burn and die.

Cannabis potassium deficiencies can cause your cannabis leaves to turn white, yellow, brown or burnt looking, but the inside veins almost always stay green. Sometimes a Potassium deficiency is made worse by overwatering, as was the case with this plant.

Sometimes you’ll get something that looks a lot like tip burn with a potassium deficiency, but it goes in further than nutrient burn, and with a potassium deficiency you also see yellowing between the leaf margins

Sometimes the burn can appear pale, bleached or yellow, instead of brown. If you look in the background of this pic, you can see some of the leaves have turned brown in addition to the bright yellow leaf in the front. These are all signs of a marijuana potassium deficiency.

Potassium deficiencies are commonly mistaken for other nutrient problems!

Sometimes the first symptoms of a cannabis potassium deficiency look a lot like nutrient burn. One difference is the edges of the leaves will also start turning brown, where nutrient burn usually only affects the tips. And unlike with nutrient burn the leaves of a potassium deficiency turn yellow in the margins, especially near the burn edges.

This is not nutrient burn, it’s actually the first stage of potassium deficiency!

Could it actually be light burn?

Keeping your grow lights too close, for example with powerful LEDs and HPS grow lights can give your plants “sunburn” even if the temperature is cool! This can sometimes look like exactly like a cannabis potassium deficiency when the true problem is your grow lights are too close to your leaves.

These leaves look like they have a potassium deficiency but the symptoms are actually caused by light burn (grow lights being kept too close)

Is it actually light burn?

Solution for Potassium Deficiency in Cannabis

Note: Sometimes a cannabis potassium deficiency (like all deficiencies) can be triggered by stressful conditions (for example overwatering, heat, transplant, etc) and may clear up on its own after the period of stress is over. If you only see one or two affected leaves near the bottom of the plant, and the problem isn’t spreading, I wouldn’t worry too much about it!

1.) Make Sure It’s Not Light Burn

When a cannabis plant is kept too close to the grow lights, it can get light burn which looks almost exactly like a potassium deficiency. If you’re using powerful lights like an LED or MH/HPS, consider moving the light away a few inches further away to see if that stops the problem from spreading. LEDs or MH/HPS should never be kept closer than 12″ away, and most models should be kept further. How far away do I keep my grow lights?

Learn more about cannabis light burn

2.) Use Good Sources of Nutrients

Most cannabis growers don’t need to add more nutrients if their leaves are experiencing a nutrient deficiency. In fact, most growers have actually already given plenty of potassium to their cannabis plants, whether they meant to or not. If you’re using quality soil or cannabis-friendly nutrients, you probably don’t need to worry about adding more patassium.

Potassium deficiencies are generally more likely to appear when a grower is using heavily filtered or reverse osmisis (RO) water to feed plants, but as long as you’re giving your plants a good source of nutrients, you probably need to…

3.) Adjust pH to Correct Range

But the reason most growers see potassium deficiencies is because potassium is best absorbed at lower pH ranges. When the pH gets too high, your plant may exhibit signs of a potassium deficiency even if it’s physically there near the roots.

Learn how to manage your pH when growing cannabis.

In soil, potassium is best absorbed by the roots in the 6.0 – 7.0 pH range

In hydro or coco coir, potassium is best absorbed by the roots in the 5.5 – 6.5 pH range

4.) Watch Leaves for Recovery

If you suspect your growing cannabis plant has a potassium deficiency, flush your system with clean, pH’d water that contains a regular dose of cannabis-friendly nutrients. Old damaged growth will likely not recover. Watch plant over next few days to make sure that the problem stops spreading to new growth.

If you cannot get rid of your potassium deficiency and want to look at more pictures of cannabis leaf symptoms…

Diagnose my sick plant!

The post Potassium Deficiency appeared first on Grow Weed Easy.

This cannabis plant suffered from the grow light being too close along with major heat stress during a heatwave in Southern California

Important for Hydroponic Growers! High temps can trigger root rot, a serious problem that can kill your plants.

Cannabis will also display heat stress when grown outdoors in hot, dry weather, especially when not given enough water.

When the heat gets too high, the edges of the serrated leaves will begin to curl up even if there are no burns or other signs of light stress.

When the heat gets too high, the edges of the leaves will begin to curl up and the leaves will begin to “cup.”

Heat Stress

Very low humidity can make plants more likely to get stressed by the heat. Sometimes you’ll get symptoms that look like heat stress even if it’s not that hot, and the symptoms are worse because the plant is being affected by very low humidity! Dry, hot air will commonly tip up the edges of leaves like this:

Heat stress is even more damaging in the flowering stage since plant is no longer growing many new leaves. Indica-leaning strains are most prone to heat damage in the flowering stage. Heat damage during budding will reduce your yields by demolishing many of your most important leaves, while also causing buds to grow airy with ugly foxtails.

Even though the grow lights were turned off, this is what happened to an indica-leaning plant overnight after being exposed to 105°F (40°C) temperatures during a heat wave.

If flowering cannabis plants are grown under too-hot conditions for a long time, sometimes they respond by growing new buds on top of the old ones. When you see extensive growth on top of the buds closest to the grow lights, that’s a sign that the grow light is too close or the temperature is too high. Some people call the new growth (which often grows in spires) “fox tails.”

If it seems like your cannabis plants are completely ready for harvest, but they keep putting out new white pistils at the top of the plant, it might just be heat. If that’s the case, pay attention to the lower growth to decide when to harvest.

Heat during the flowering stage also causes fox-tails, which are airy and don’t have much substance to them. It’s basically the same response as growing new buds on top, it just looks a little different on some plants. The plant is basically “abandoning” the original heat-damaged bud to try to make a sad new one.

Example of unwanted “fox-tailing” caused by too much heat

Solution: Get a way to monitor temperature. Control heat by whatever means necessary using the steps outlined below.

Learn 5 secrets to controlling heat in the grow room.

Indoors, find a way to lower the temperature and/or increase the circulation in the grow room or grow area if heat is the problem. Having a small fan blowing over the tops of your plants will help prevent hot spots from forming directly under your grow lights. How far away should you keep your grow lights from your plants?

You may consider removing grow lights further away from the tops of the plants if heat is a problem.

When growing cannabis, it’s best to try to keep things at a comfortable room temperature at all times for optimal growth. If it’s too hot for you, it’s probably too hot for your plants.

Keep roots cool!

If you can keep your roots cool, it will help your plant deal with heat affecting the top of the plant. If there’s some way to protect the roots from heat, do it!

When cannabis plants are recovering from heat shock, some growers recommend using seaweed kelp extract (often available as a convenient liquid fertilizer) to help plants recover from the stress and possible even protect plants from heat stress in the future.

Many indoor setups will require that you vent out hot air using a fan and/or an exhaust system. By creating good suction with an efficient exhaust system and adding a carbon scrubber, you can also pretty much scrub all smells from the grow room. Learn more about controlling odors in the grow room.

An oscillating fan will circulate air in the room as well as provide a gentle breeze for your plants, and a small one will cost less than $20.

Learn everything you need to know about controlling temperature in the grow room.

Outdoors, you have less options to reduce heat during a heat wave, but you are able to monitor your local weather via weather forecasts.

Read the full tutorial on how to help outdoor cannabis plants in the heat.

It is possible to partially shield your plants when you know the temperature is going to get hot. You can also adjust your watering schedule to make sure plants at least have plenty of water.

Some things to try when you know the weather outside is going to be hot or dry:

• water plants in the evening or early morning to help prevent water evaporation during the hottest hours
• keep roots cool – for example by putting your potted plant in a ceramic pot to help insulate the roots from the sun. I’ve also heard of growers digging a hole in the ground to place their potted plant inside, because the ground is usually cooler than the air when the temperature gets high
• kelp extract for roots – provide a small amount of liquid fertilizer that contains seaweed kelp extract (can help protect against heat stress)
• increase shade to reduce the heat experienced by plants – you can use an old sheet or other cloth as a short term solution, or get a professionally made “Sun Shade Sail” which is made particularly to create shade outdoors. It’s important to remember that giving plants shade for more than a few days will make them less “hardened” to the sun, and you may need to reintroduce full sunlight back slowly to prevent them from getting shocked from the light intensity
• move potted plants – luckily with potted plants, it’s usually easier to move them out of direct sunlight during a heat wave
• take extra good care of heat-stressed plants – when cannabis plants appear heat-stressed, try to baby them as best you can, and offer shade during the hottest days.

When growing cannabis outdoors, it can often take a few weeks for plant to recover after a hot or dry spell, so prevention is the best medicine for outdoor plants.

Jump to…

Picking the right grow light

Light-Stress & Light-Burn

Air Circulation & Exhaust Tutorial

7 Tips to Growing Top-Shelf Buds

The post Heat Stress appeared first on Grow Weed Easy.

Solution For Cannabis Zinc Deficiency

Note: Sometimes a cannabis zinc deficiency (like all deficiencies) can be triggered by stressful conditions and may clear up on its own after the period of stress is over. However, to minimize damage it’s important to react to any growing problem as quickly as possible, especially in the flowering stage.

1.) Adjust pH to Correct Range

The most common reason growers will see a zinc deficiency is when the pH at the roots is too high. Zinc tends to get locked at higher pH levels and is better absorbed by the plant in a more acidic root environment.

If you suspect your growing cannabis plant has a zinc deficiency due to too-high pH, flush your system with clean, pH’d water. This will remove any nutrient salts that may be affecting the uptake of zinc and help restore pH to the proper levels.

• In soil, zinc is best absorbed by the roots in the 6.0 – 6.5 pH range (although it’s generally recommended for soil growers to keep pH in the 6.0-7.0 range, zinc tends to be absorbed better on the lower side)
• In hydro, zinc is best absorbed by the roots in the 5.5 – 6.0 pH range (although it’s generally recommended for hydro growers to keep pH in the 5.5-6.5 range, zinc tends to be absorbed better on the lower side)

Learn how to manage your pH for growing cannabis.

2.) Give the Right Nutrients

The truth is, most cannabis growers don’t need to add more zinc in response to a zinc deficiency!

In fact, most growers have actually already given plenty of zinc to their cannabis plants since it is found abundantly in most tap water. If you’re using quality soil or cannabis-friendly nutrients, you probably don’t need to worry about adding more zinc. In general, zinc deficiencies are more likely to appear when a grower is using heavily filtered or reverse osmosis (RO) water to feed plants since any zinc has been removed, but pH is a much more common reason growers see zinc deficiencies in their cannabis plants.

3.) Take Good Care of the Roots

Zinc deficiencies can show up with the plant is having root problems or if the plant is overwatered, even if the pH is right and the zinc is there. Proper watering practices help plants grow healthy and avoid a host of problems!

4.) Watch for Recovery

After going through all the above steps, watch to make sure that the zinc deficiency starts to clear up within a few days to a week or so. The damaged leaves may not recover completely, but you know you’re in the clear when you stop seeing symptoms on new leaves.

If you cannot get rid of a cannabis zinc deficiency, please consult our 7-Step Cure to 99% of Cannabis Growing Problems

The post Zinc Deficiency appeared first on Grow Weed Easy.

Problem: Your cannabis plant can only withstand a certain amount of light. After a certain point, your cannabis will start turning yellow or otherwise exhibit signs of stress on the leaves near the sources of light and/or heat.

How far away do I keep grow lights from my plants?

Light burn usually causes yellow leaves at the top of the plant directly under the grow lights (though it can appear on older leaves that have been exposed for a long time).

Sometimes the first sign a plant is getting too much light is all the leaves start pointing up or “praying”, like this (though sometimes you don’t see any symptoms until the yellowing starts)

With light burn, often the inside veins stay green. Yellow leaves won’t fall off or be plucked off easily, unlike a nitrogen deficiency where leaves fall off on their own.

The leaves closest to the light may appear much more pale than the rest of the plant, and tips may turn yellow.

Another example of yellow tips from light burn

Sometimes light burn causes edges of leaves to turn up. If it goes on a long time, the leaves also start to become crispy and can even break off if you try to bend them

You may noticed just the tallest colas getting droopy, which is sometimes a sign the light is too intense (though it could also be caused by root problems or over/under watering)

Light burn is often mistaken for a Nitrogen deficiency which makes wilting yellow leaves. Nitrogen-deficient leaves fall off on their own, while light-burned leaves are hard to pluck off. A nitrogen deficiency starts from the bottom of the plant and moves up, while light burn often is worse at the top of the plant.

Cannabis light burn usually affects the top leaves closest to the grow light

A Nitrogen deficiency creates yellow leaves at the bottom of the plant as the Nitrogen is sucked out of the oldest leaves to feed the top of the plant. On the other hand, light burn produces yellow leaves at the top of the plant under the grow lights because the leaves have worked too hard and/or too long from the light being too close. The leaves aren’t able to keep up with regular plant processes.

Imagine sitting outside all day under a scorching sun, possibly for days on end. Even if you could handle it for a day or two, it might wear you down over days or weeks.

How can there be too much light if there’s no heat? Read the full guide

It’s probably light burn if mostly just the leaves closest to the lights are turning yellow

With cannabis plants that have light burn, your leaves can sometimes become yellow or red/purple, possibly with brown spotting, often with burnt tips/edges and margins that stay green. Other problems, like nutrient problems, can trigger or make the symptoms of light burn a lot worse. Leaves may also appear generally burnt in places when there’s too much light, especially when combined with heat or nutrient problems.

Nutrient deficiencies make light burn worse!

If you see light bleaching and unhealthy discoloration only on the parts of the plant directly under your grow light, or only on older leaves that are exposed to the light, it often means it’s too bright for your plants and you should move your grow lights further away! If your plant is also having other problems, it is much more likely to be affected by light burn. A healthy plant can withstand higher light levels than a sick plant.

If the lights are only slightly too close, maybe just an inch or a few cm, the yellowing from light burn may happen slowly over the course of days (or even weeks!) because leaves are dying early instead of immediately. Because of that, light burn may first appear on somewhat older leaves, which can be confusing and make it hard to diagnose.

This cannabis seedling is being burned by too-close LED grow lights

Another example of light burn from an LED grow light being kept too close to the plants

These leaves of this LED-burnt plant started curling upwards

This cannabis seedling basically grew up into the grow light! The heat from the bulb caused massive burning everywhere it touched. If a plant’s leaves directly touches the lights, it leaves “burns” from the heat of the bulbs.

This plant was green and healthy through the vegetative stage under an LED grow light, but the leaves started dying soon after flowering started (even though that distance had been fine in the vegetative stage). The reason was the LED was too close. This is also very common with LED grow lights with just read and blue diodes, without any diodes in the green spectrum.

These plants seem apparently healthy, but the top leaves keep getting lighter and lighter, in this case from a 600W HPS that was kept just under a foot (30cm) away. The leaves slowly turned yellow over the course of a few weeks, getting light burn even though the temperature was a comfortable 75°F (24°C).

These yellow leaves were caused by an LED grow light that was too close. If you don’t realize it’s light burn, the symptoms are inexplicable!

A mild case of marijuana light burn is often mistaken for a nutrient deficiency or a pH problem, but if you look closely, the symptoms are concentrated directly under the grow light.

Light Bleached Cannabis Buds Sometimes Turn White

This is how you get “albino” or white buds. Light bleaching is most common with high-power LEDs and HPS grow lights because these can be brighter than the sun. Basically, bud bleaching is what happens when buds get too much light, kinda like how hair can get bleached if you spend plenty of time in the sun. Except a “sun-burnt” bud is often less potent, and may have lost it’s “cannabis” smell!

Buds which have been bleached tend to be low potency or even have no potency (no available THC or other cannabinoids). Therefore you should avoid light-bleaching your plants at all costs!

Sometimes light-bleached cannabis will get mis-labeled as “albino cannabis” or “white cannabis” but the truth is that the white color is not healthy, so this is not a desirable trait (even if it looks pretty cool).

Most of the Time, Light-Burned Buds Appear Burnt

Often though, light burned buds look like they’ve been burned.

LED-burnt cannabis buds – notice how all the tiny “sugar leaves” have turned yellow or brown

In this case the LED-burn caused the leaves closest to the LED to turn red. Although the buds smoked pretty well anyway, they definitely weren’t as pretty as they could have been!

The leaves too close to the LED grow light turned yellow and wilted. For some reason, cannabis plants seem a lot more prone to light burn after they start flowering.

Another example of a bud that has light burn from a too-close LED

Light burned bud on top, healthy bud below

Solution: If your marijuana plants are getting too much light, try removing some of the lights or moving your grow lights further away from the tops of the plants. If you can’t move the light further away, bend your plants over so the tops are further away or if your plant is still in the vegetative stage you might even consider cutting off the top of the plant to remove some of that height.

Reduce power of grow lights and/or move them further away from your plant
(How far away do I keep grow lights from my plants?)

It is unlikely for your plants to get “light-burned” from the sun when growing outdoors, and they definitely can’t accidentally grow into the sun. Outdoor plants can show signs of light stress if plants were used to shady conditions and moved into direct sunlight without time to get accustomed to the brigher light levels. It also may be possible in extreme high light conditions if the plant is unprotected but in general cannabis plants like a lot of light.

When making changes to your plant’s environment, it’s best to make changes relatively slowly if possible. For example when moving a cannabis plant from indoors or outdoors you might consider giving the plant some shade for a few days before moving it into full sunlight.

Sometimes heat stress can look like light stress. When learning how to grow cannabis, it’s best to try to keep things at a comfortable temperature at all times for optimal growth. If it’s too hot for you, it’s probably too hot for your plants. Outdoors, it’s a lot harder to control temperature, but there are steps you can take to protect your outdoor plants from the heat including supplementing with sea kelp, partially covering them and making sure they’re well watered.

5 Ways to Deal with Heat When Growing Cannabis Indoors

Jump to…

7 Step Fix to 99% of Cannabis Growing Problems

Pictures of Cannabis Plant Problems

What does pH have to do with nutrient deficiencies?

10-Step Quick Start Guide to Growing

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