What Causes Cannabis Leaves to Get Dry or Crispy?

Last updated Feb 15, 2024

by Nebula Haze

The first crispy leaf appears, like a brown spot on a perfect apple. “I’m sure it’s nothing,” you tell yourself.

The first crispy cannabis leaf appears, like a brown spot on a perfect apple. "I'm sure it's nothing," you tell yourself.

But a few days later, imagine waking up to find a dry, crispy leaf wasteland where your beautiful, healthy green cannabis plants used to be. Some leaves have burnt edges, yellowing, or brown spots. You peer closer and notice many crispy leaves are tinged with brown or yellow undertones.

The first crispy leaf appears, like a brown spot on a perfect apple. "I'm sure it's nothing," you tell yourself. But the next day, imagine waking up to find a dry, crispy leaf wasteland where your beautiful, healthy green cannabis plants used to be. Some leaves have burnt edges, yellow tips, or scattered brown spots. You peer closer and notice many crispy leaves are tinged with brown or yellow undertones. Alarm bells ring. You know your cannabis plant is crying for help, but what is the matter? Crispy leaves could signal environmental stress, improper watering, a nutrient issue, or even a pest infestation. Ultimately, crispy leaves are your cannabis plant telling you that something is disrupting its growth and leaf health.

Alarm bells ring. You know your cannabis plant is crying for help, but what is the matter? Crispy leaves could signal environmental stress, improper watering, a nutrient issue, or even a pest infestation. Ultimately, crispy leaves are your cannabis plant telling you that something is disrupting its growth and leaf health.

If you see symptoms spreading through your marijuana plant, you need to react quickly. For example, this cannabis plant’s crispy, dry leaves with yellowing, curling, and spots are caused by a mixture of heat and light stress. Simply moving the grow light further away will help keep the dry leaves from spreading. Don’t wait!

Example of dry, crispy cannabis leaves with lots of brown spots and yellowing - caused by too much light and heat in the cannabis grow room!

Sometimes a nutrient problem can cause leaves to become dry and crispy, like this nitrogen toxicity. The sooner you fix the underlying issue, the sooner the symptoms stop getting worse.

A Nitrogen toxicity can also cause certain leaves to turn yellow, but other than that it looks nothing like a cannabis nitrogen deficiency

If you ignore crispy cannabis leaves, the symptoms can spread from the leaves to the buds and you may end up with off-color, crispy buds after harvest (instead of beautiful, sticky buds).

If you ignore crispy cannabis leaves, the symptoms can spread to the buds and you may end up with off-color, crispy buds after harvest (instead of beautiful, sticky buds).

Not necessarily the end of the world, but not ideal cannabis bud quality either.

Dry crispy buds are not the end of the world, but not ideal cannabis bud quality either.

Ever walked into your grow room and seen dry, crispy cannabis leaves? This frustrating problem can hit any grower, especially during the flowering stage while plants are putting most of their energy into making buds. But there’s good news – you CAN fix it! Let’s not waste any time worrying. It happens, and I’m here to help you figure out why. Chances are, it’s a simple fix and your plants will be rocking those gorgeous buds soon enough.

 

7 Most Common Reasons for Dry, Crispy Marijuana Leaves

Sometimes crispy leaves can be normal, but most of the time, this means that something is wrong with your cannabis plant or the growing environment. Today, I’ll help you quickly identify what’s ailing your marijuana plants so you can fix the issue at once and get back to growing amazing weed! Check out our Diagnose Your Sick Marijuana Plant page if you still don’t see your symptoms here, but without further ado…

 

1.) Could Be Normal – for example, old or light-starved leaves may become dry or crispy.

Usually, the bottom-most leaves start to get a little crispy or yellow as they start getting old. If your dryness problem is just affecting the oldest leaves that don’t get much light anymore, you likely don’t need to worry.

As your cannabis plant grows, it’s normal for the first few sets of leaves to turn yellow and die, especially if they’re constantly in shadow. In fact, almost all leaves will eventually die if they stop getting light. So if it’s only the lowest leaves getting crispy, it’s probably nothing to worry about.

Solution: If the problem is just appearing on old leaves which aren’t getting light, you probably don’t need to do anything. Just keep an eye on the plant for other signs of stress.

 

2.) Light Burn – leaves close to the light are dry and crispy, sometimes you see yellow tips

If the dry or crispy leaves are worst directly under your grow light, it’s possible that the crispiness is a result of ‘light burn’ or ‘light stress’.

Light Burn (can happen even if the temperature is cool because the grow light is too close)

Example of cannabis symptoms caused by light burn. Yellowing top leaves under the grow lights, and the leaf margins often stay great. With light burn, leaves may turn red instead of yellow.

Cannabis suffering from light stress

Light stress from the grow lights being too close can also cause yellow tips.

Yellow tips from the grow light being too close (light stress).

Example of yellow tips from light burn (this is NOT nutrient burn)

The tips and edges of the cannabis leaves that are closest to the grow light may start to “tip up” and get crispy. You can tell that light stress is the cause because only the cannabis leaves closest to the grow light are affected.

Light stress often starts at the tips and edges of the cannabis leaves that are closest to the grow light.

If a cannabis plant’s leaves are subjected to high light levels for a long time, the curling at the serrated edges may continue to get worse until the leaves become totally brittle. At that point, if you try to smooth the leaf out, the crispy edges may just crunch and fall off.

If a cannabis plant's leaves are subjected to high light levels for a long time, they may start curling at the serrated edges.

Solution: Whenever you notice leaf symptoms are worse close to the grow light, the first step is to move the light further away (or turn down the power) until the symptoms stop spreading.

 

3.) Heat Stress – high temperatures can cause leaves to turn dry and crispy.

Even if the grow light is a good distance away from your cannabis plants, they can still get stressed out by excessive heat. Cannabis plants generally prefer temperatures under 85°F / 30°C, though some strains are more sensitive to heat (shorter, bushier strains are often more sensitive to heat than the longer, lankier strains).

Most plants are fine with a few hot days, but if it’s hot every day for weeks, your plants can really start to suffer. The majority of marijuana plants can handle a small heat spell, but they don’t want to live in a desert.

Heat Stress

A little heat will cause some problems like leaf tacoing and discoloration, like you can see with this heat-stressed marijuana seedling

Heat Stress on a thirsty outdoor cannabis plant

This plant is getting spots and other discoloration of the leaves because it's in too-hot conditions.

Young cannabis plants can adjust to heat, but heat stress causes the most damage for a cannabis grower in the second half of the flowering stage. That’s because buds tend to develop with lower potency and smell in overly hot conditions.

A hot day causes these leaves to shrivel up overnight

Solution: If it’s regularly above 85°F / 30°C, you could take steps to vent out extra heat away from your plants. If growing in a grow tent, that just means to install a strong exhaust fan pointing out from one of the top port holes. This should equalize the temperature in the tent to just a bit above the temperature of the room. If the entire room is getting hot, you may need a window fan to vent hot air outside. If the outdoor air is also hot, you may need an AC (fans can move air around to equalize the temperature between areas, but only an AC can actually make air colder).

Here’s a full tutorial on how to vent heat out of the cannabis grow space.

Want more help? Learn 5 secrets to controlling heat in the grow room. Check out this list of 3 proven supplements that can help prevent heat stress. And remember, cannabis plants are more resistant to heat stress when grown under LED grow lights vs grow lights that use bulbs like HPS, LEC, or fluorescent lights.

 

4.) Nutrient Burn – tips of leaves appear brown and burnt

If the dryness is associated with the brown curling tips of leaves, it’s possible that you are giving your cannabis too many nutrients. This disrupts the natural flow of nutrients in the plant and causes the tips of leaves to die. In the cannabis growing world, this is almost universally referred to as “nutrient burn”. Nutrient burn often appears on leaves after increasing the overall amount of nutrients or adding a new supplement.

Nutrient burn is brown and appears on the tips of leaves. If it gets worse, the ends start to curl up and flake off easily.

Cannabis nutrient burn - burnt tips curling up

Solution: If you see signs of nutrient burn on cannabis leaves, it usually means you need to reduce your nutrient levels, for example, by adding less nutrients to your water. Read the full tutorial on how to deal with nutrient burn.

 

5.) Nutrient Deficiency – can cause a variety of spots, discoloration, or other symptoms on leaves.

Another reason your cannabis may get crispy or dry leaves is due to some sort of nutrient deficiency. For example, certain deficiencies like a Potassium Deficiency can cause discolored leaf edges and crispy leaves.

A potassium deficiency causes the edges of leaves to appear burned

Yellow leaves with brown edges and tips are the signs of a weed potassium deficiency

If you’re using cannabis nutrients but still seeing a nutrient deficiency, it is often caused by either incorrect pH at the roots (or one of the other problems listed on this page). If the pH is too high or low at the roots, your cannabis plant can’t absorb the nutrients properly. So you could be giving them the perfect amount of nutrients, but if the pH is off, you’ll still see nutrient deficiencies. That’s why if you think you may have a nutrient deficiency on your cannabis plants, the first thing to do is check the pH of your nutrient water.

Nutrient Deficiencies (These Were Caused by Incorrect pH)

The leaf edges and tips turn bright yellow during a cannabis copper deficiency

This pot plant is showing the signs of a sulphur deficiency (odd yellowing of leaves starting from the center)This marijuana plant appears to have a potassium deficiency (odd yellowing of leaves starting from the edges) which can look like nutrient burn but is actually caused by incorrect pH

A young cannabis plant with the yellow leaves of a potassium deficiency

Magnesium Deficiency

This marijuana leaf is showing signs of a magnesium deficiency (yellow stripes in between the veins)

Iron Deficiency

Example of a cannabis plant that has yellow leaves as the result of an iron deficiency

The best way to prevent nutrient deficiencies is to make sure you’re giving your plants the right type of nutrients and pHing the water to the proper level depending on your growing medium. But that doesn’t mean more is better. It’s important not to overload your plants with too high levels of nutrients.

Too Much Nitrogen (Nitrogen Toxicity) causes dark green leaves that often feel dry and crispy

A Nitrogen toxicity can also cause certain leaves to turn yellow, but other than that it looks nothing like a cannabis nitrogen deficiency

How to Fix a Nutrient Deficiency on Cannabis Plants

  • Is it PH?
  • Do you need Cal-Mag?
    • If you’re seeing a Magnesium or Calcium deficiency, consider getting CaliMagic, a Cal-Mag supplement that is made for plants (you should always add Magnesium and Calcium at the same time because these two nutrients work together closely in the cannabis plant, and are important in iron uptake).
  • Reduce light until symptoms stop spreading.
    • Move the lights up a few inches or reduce the light power. This lowers how much light your leaves have to process each day.
    • If grow lights are on a 24/0 schedule, change to 18/6 so plants get a 6-hour dark period every day. This tends to make plants more resistant to problems.This extra nighttime break and slightly lower levels of light will help an ailing plant recover more quickly.
    • Once the plant is growing fast and healthy again, you can go back to full power.
  • Do you have good nutrients?
    • If you don’t know what type of nutrients to use, I recommend using the General Hydroponics Flora trio for hydro, coco, or soil. The GH trio gets some of the fastest growth of any nutrients I’ve tried with cannabis so far. If you want to grow with mostly organic nutrients, the Fox Farms Soil Nutrient Trio is great for your soil grow and has a lot of organic ingredients with only a minimal amount of mineral nutrients.
  • Learn everything you need to know about cannabis nutrients here.

Fox Farm Soil Trio contains mostly organic sources of cannabis nutrients and gets great results in soil grows.

Get the Fox Farm soil nutrient trio for growing cannabis on Amazon.

General Hydroponics Flora trio is great for soil, coco coir, or hydroponic grows, and gets extremely fast cannabis growth when used as directed.

General Hydroponics Flora trio is great for soil, coco coir, or hydroponic grows, and gets extremely fast cannabis growth when used as directed

 

6.) Root Problems, Root Rot, or Bad Watering Practices – almost always accompanied by droopiness.

Chronic overwatering can sometimes cause unusual deficiencies even if the pH is spot on, like this plant grown in muddy soil. The biggest sign that these symptoms are caused by overwatering and not pH (or something else) is that the plant is always droopy.

This apparent cannabis potassium deficiency looks like a pH problem, but it's actually been caused by overwatering

Another example of a deficiency that’s actually caused by overwatering (notice how this seedling is also droopy).

Another example of a deficiency caused by overwatering

Regular overwatering of cannabis plants can cause a variety of unusual symptoms, including dry or crispy leaves, that are often mistaken for nutrient deficiencies or other problems.

Regular overwatering of cannabis plants can cause a variety of unusual symptoms that are often mistaken for nutrient deficiencies or other problems.

This cannabis plant started getting crispy leaves and brown spots after being overwatered, causing a calcium deficiency.

This cannabis plant started getting crispy leaves and brown spots after being overwatered, causing a calcium deficiency.

Root Rot

Example of a sick cannabis leaf caused by root rot

The burnt discolored leaves of a cannabis plant with root rot

 

7.) Bugs or Mold – visible bugs, webbing, spots on the leaves, residue on leaves, bite marks, etc.

If your plant gets bugs, it can cause lots of symptoms including dry, crispy leaves.

Dry, crispy, yellow leaves caused by a fungus gnat infestation

Cannabis leaves damaged by fungus gnats

Bud Rot

One of the first signs of bud rot is often yellow leaves where the mold is taking hold

Bud rot causes all the nearby cannabis leaves to die, which turn dry, brown, and crispy.

Bud rot causes all the nearby cannabis leaves to die, which turn dry, brown, and crispy.

Broad Mites

Example of leaf damage from broad mites or russet mites

 

Other Possible Causes

If you accidentally spill full-strength nutrient-filled water on some of your leaves and don’t wipe it off, it’s possible that they will get burned from this as well, either from the nutrients or the lights being magnified by the water.

Another thing to think about is, “Did anything different happen right before I started seeing problems?” Was there a hot day, a new supplement, or some other change? Sometimes this might give you a hint to the cause.

Did Anything Different or Unusual Happen Recently?

If you’ve gone through this tutorial and are still having problems, check out this page which explains the symptoms of nutrient deficiencies in marijuana.

If you have anything to add, or if you have any other questions, I’d love to hear from you regarding your experiences growing weed.

If you’ve made it this far, you should have everything you need to get your plants thriving again!

 


 

More Resources for Cannabis Plant Problems

Cannabis Problems Guide

Diagnose Your Sick Plant

Bugs & Other Cannabis Pests

How to Prevent Nutrient Deficiencies

7-Step Remedy That Fixes 99% of Grow Problems

 


 

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