You are hereWhich Nutrients Should You Be Using?
Which Nutrients Should You Be Using?
by Nebula Haze
Table of Contents
If you've decided to start growing cannabis for the first time, trying to figure out the best nutrients for your setup can be very confusing. There are many nutrient companies, and each one creates multiple types of nutrients with different purposes.
The most important thing is to make sure you give your plants the right amounts of nutrients at the right time. There are two main life stages for cannabis plants, and each stage has different nutrient requirements.
For the best results, your cannabis needs the following nutrient ratios....
Where is this information? Most nutrient bottles display 3 numbers, often called N-P-K, which stands for Nitrogen, Phosphorus and Potassium
Why "K" for Potassium? The atomic symbol of Potassium is "K" from Neo-Latin kalium.
In other words, you want to use a “Vegetative” (high Nitrogen) or "general purpose" nutrient formula for the first stage of life known as the vegetative stage. If using high-quality soil, you can skip vegetative nutrients for the first 3-4 weeks while your plant uses up the nutrients in the soil, otherwise you should start with vegetative nutrients around the time your plant opens its first leaves.
Use a “Bloom” (low Nitrogen) nutrient formula with plenty of P & K for the flowering stage. Start using bloom nutrients when buds start forming to make sure your plant gets plenty of Phosphorus & Potassium, which are crucial to bud development.
Phosphorus tends to increase the number of flowers, while Potassium helps increase the bulk/weight of flowers. Be careful, though because going overboard with either one can burn your plants!
The main thing is to avoid giving too much Nitrogen in the flowering stage, as it can discourage bud development in the flowering stage and add an unpleasant taste to buds, which is why a general purpose plant nutrient isn't a good choice in the flowering stage.
In a pinch, nutrients for "cactus" or "succulents" can be used in the flowering stage until you get better nutrients because they usually have low amounts of N and plenty of P & K.
Note: Don’t use any type of time-released nutrients (like fertilizer spikes, or "slow release" Miracle-Gro soil) because they deliver too much N in the flowering stage and may reduce bud growth.
Cannabis needs plenty of P & K to make buds in the flowering stage!
It may surprise you that the most common reason growers get nutrient deficiencies is because the pH is too high or too low. This happens even if the right amounts of nutrients are present, because your weed simply cannot absorb the nutrients if the pH isn't in the correct range.
Optimum cannabis pH for..
Soil: 6.0 - 7.0
Coco Coir: 5.5 - 6.5
Hydroponics: 5.5 - 6.5
Checking the pH will make a huge difference to your grow by keeping plants vibrant and healthy. It only takes a few minutes each time you water your plants! If you get a digital pH pen, it only takes seconds to test your pH!
This is a common question we get at Grow Weed Easy: What are the major differences between organic and chemical nutrients? It's not a matter of which one is better, because they're good at different things.
- Better Smell & Taste to Buds - Many growers believe organic-based nutrient systems will create the most fragrant and "smoothest" buds. Some of the best benefits to smell and taste seem to come from using composted soil that's been amended with nutrients from natural sources. This creates a living soil with colonies of beneficial microorganisms, and is often associated with a bolder taste and smell in buds. However, watering your plants with liquid nutrients that just happen to be organic will likely not get the same level of results.
- More Natural - Especially when growing in a living soil, you're creating a home for your roots that is as close to nature as possible (only better because you're making sure your plant gets everything it needs!)
- Not for Hydro - Organic nutrients are not a good choice for hydroponic systems because any organic matter can cause unwanted stuff to grow in your reservoir. Let me just say this, as of yet, I've never seen organic hydroponics go well for someone, though I wouldn't mind being proven wrong ;)
General Organics offers a "GO Box" with their famous organic base nutrients plus their best organic supplements
- Increased Potency - While organic nutrients may increase the smell and taste of buds, chemical nutrients may increase the potency.
- Faster Growth - Chemical nutrients provide nutrients to plants in the most easy-to-absorb forms possible. This results in somewhat faster growth than if the nutrients have to be broken down in the soil by a colony of microorganisms before they become available to your plant.
- Only Choice for Hydro - These are the best cannabis nutrients for hydroponic systems because they are less likely to cause stuff to grow in the water reservoir. However, chemical nutrients can also be a great choice for soil or coco because of the increased potency and faster growth!
The General Hydroponics Flora trio is a chemical-based nutrient that's so popular it's even been used by NASA to grow plants in space!
Don't want to use nutrients at all? Learn how to compost your own super soil (or buy super soil pre-made online)! Super soil compost contains all the nutrients your plant will need from seed to harvest so you just need to add water, and as an added bonus, with composted super soil you don't need to worry about maintaining your pH! Instead, the composting process develops a colony of microorganisms in your soil that will automatically take care of the pH for your plants (like in nature), while slowly providing nutrients on demand.
Super soil compost has been amended so no additional nutrients are needed. Just add water!
- Nutrient Ratios - different brands have come up with different ratios between nutrients that they believe is optimal for each stage of growth
- Ingredients - there are many different combinations of chemical and organic compounds that can add up to same nutrient ratios, and each compound reacts differently with each other. This means you can see two nutrient bottles with the exact same NPK ratios on the bottle, but each will actually provide somewhat different levels of nutrients to your plants.
- Soil or Hydro - it's really important to match your growing medium with your nutrients. "Soil" nutrients are different from "Hydroponic" nutrients so make sure you're getting the right kind! Coco coir is generally considered a type of hydroponics when it comes to nutrients, and there are also nutrients specifically designed for coco coir.
- Don't confuse supplements for nutrients. If the NPK ratios are really low (like 0.2-0.2-0.1) it means that this product is some type of supplement, not a base nutrient. As long as you provide the right NPK and micronutrients by using base nutrients, you are already giving your plant everything it needs to grow. Supplements can be nice, but sometimes going overboard with supplements can cause unwanted reactions between nutrients or possibly burn your plant. Just to be safe, for your first grow only use supplements from the same company as your base nutrients (to minimize reactions), and try to pick just the one or two supplements that appeal to you the most (to minimize the chance of burn by going overboard). Nutrient companies will happily sell you supplements you don't actually need so it's up to you to narrow it down to just a few!
Now that you understand the basics, are you ready to learn how to figure out the best marijuana nutrients for your setup?
Here are several examples of trustworthy nutrient brands that work well for growing cannabis. These nutrients have been extensively tested by growers and are known to produce great results!
- General Hydroponics Flora Trio - Coco Coir & Hydroponics
- General Organics GO Box - Soil (Fully Organic)
- Fox Farms Nutrient Trio - Soil & Coco Coir
- Botanicare - Soil & Hydroponics
- House & Garden - Soil, Coco Coir & Hydroponics
- Canna Coco - Coco Coir
A tried and true favorite of mine, the GH Flora trio works very well for growing cannabis. Although it can be used in soil as well, it does best in coco coir and especially full hydroponic applications. I've used this nutrient system for over half a decade and I've been thrilled with it. Recently I started testing new nutrient systems so I can report back to our readers like you, but based on my years of success I know you'll be happy with the Flora trio. Best for...
- Coco Coir
GH Coco Coir version
Follow the custom Coco Coir schedule I made so you don't have to figure out half the recommended dose. Also check out a grow journal featuring the GH Flora trio in coco coir to see this combo in action!
GH Hydroponic version
Check out a few different grow journals featuring the GH Flora trio in Hydro/DWC.
General Organics nutrients are made by the same people as General Hydroponics, except these nutrients are organic and formulated specifically for soil.
- Best for Soil
Easy organic solution - everything you need in one box. This kit not only has base nutrients, but also all of GO's most popular organic supplements. Here's a cannabis-friendly nutrient feeding chart (start at half the recommended strength) for the GO Box.
The FF trio is a popular nutrient system for cannabis growers that contains a variety of natural sources for nutrients like earthworm castings and bat guano, which cannabis plants thrive on. Fox Farm nutrients contain too much organic matter for DWC/hydro, but all that organic matter is great for plant roots in a hand-watered environment because it may help enhance small and flavor of your finished product. Best for...
- Coco Coir
FF Soil version
Very concentrated, less is more. "Grow Big" & "Tiger Bloom" provide most of the major nutrients your cannabis needs, while "Big Bloom" has many micro nutrients and beneficial compounds that help nutrient uptake and root health. This trio works extremely well by itself, just follow the feeding schedule (here's a PDF, here's a JPG) from Fox Farms.
Check out a grow journal using the FF trio for Soil!
FF Coco version
Use the "hydro" version of Fox Farms nutrients when growing in coco coir. Two bottles are the same as the soil trio, but the "Grow Big" bottle is formulated slightly different for a soilless grow. Follow the feeding schedule (here's a PDF, here's a JPG) from Fox Farms. Generally the Fox Farms nutrient system will prevent Cal-Mag deficiencies, but it's good to have extra Cal-Mag on hand just in case whenever growing cannabis in coco coir.
Botanicare is a great company who have been around for quite a while and whose supplements I've been using for years (specifically, their Hydroguard supplement is the most effective thing I've used to prevent root rot in a hydroponic setup). Best for...
Botanicare Soil version
The two bottles are all that's needed to get your plants successfully to harvest time, just follow the feeding schedule from Botanicare, starting at half the recommended strength. Use "Grow" for the vegetative stage (first stage of life) and switch to Bloom for the flowering stage (when plant starts making buds).
Botanicare Hydroponic version
The three bottles are all that's needed to get your plants successfully to harvest time, just follow the feeding schedule from Botanicare [PDF], starting at half the recommended strength. Hydroguard is an important root supplement that will help prevent your plant from getting root rot in a hydroponic reservoir. The KIND series has been highly recommended by several hydro growers I know in real life, and due to the high ratings this is actually the nutrient system I'm testing next. I'll have some grow journals for you soon!
From a grower: "Botanicare KIND is like the opposite spectrum [of the Botanicare Pure Blend series]. The Base is just Nitrogen and Calcium. Grow and Bloom both have most of the minerals in them, along with things like sea kelp! The Bloom is also 0-6-6. Grow at 2-2-4. So quite literally you can call the shots on Nitrogen and Calcium. That level of control hasn't been around a great deal in our market. For the savvy grower this is a pretty nice tool."
The House & Garden lineup is expensive yet remarkably effective. From a grower: “H&G was started by a top researcher from Canna. They are right outside of Amsterdam and because cannabis is legal there, so both Canna and H&G are able to do R&D using cannabis. I don't know about Canna, but I know that House and Garden makes all their own nutrients in house and they work great.” Best for....
- Coco Coir
H&G Soil version
Get a custom nutrient schedule directly from the people at House & Garden via their free online nutrient calculator.
This plant was grown using the House & Garden Line-up listed above
H&G Coco version
Get a custom nutrient schedule directly from the people at House & Garden via their free online nutrient calculator. This company was actually started by people who specialized in coco coir nutrients for cannabis, and this is one of their most popular nutrient lines!
H&G DWC / Hydroponic version
Get a custom nutrient schedule directly from the people at House & Garden via their free online nutrient calculator. Their "Aqua Flakes" lineup is supposed to be really low on salt buildup, which may help give your buds a smoother smoke and less chance of nutrient burn in a DWC setting.
Canna Coco is a very popular company as their nutrients have been specifically designed to grow cannabis in coco coir (as you may be able to tell from the name).
- Best for Coco Coir
This combo is a crowd favorite - many coco coir growers write in to tell us this is their favorite cannabis nutrient for growing in coco coir. Get a custom nutrient schedule from Canna or use this pre-made one [JPG].
From a grower: “Canna is a Dutch company and one of the best IMO. They make a great product line for growing in coco coir and test their products on real cannabis plants."
Another grower said, "Canna products are one of the only nutrient lines to be developed primarily for cannabis (and tested on live plants). They've been doing so for almost 30 years. Cost is a little higher than competitors but worth every penny.”
A different grower added, "Canna - I have only used their coco line, but it is the the highest quality you will find."
One Last Tip....
When using a complete nutrient system like the ones listed above, always start at half the recommended strength by the manufacturer, and only increase nutrient levels if your plant is getting pale. If you're giving too low levels of nutrients, the entire plant will start to appear overall pale or lime green. If you have a different nutrient deficiency (diagnose your plant here), chances are it's caused by incorrect pH, not by too low levels of nutrients.
Always start at half the manufacturer's recommendation! Most nutrient companies recommend way too much for growing cannabis!
Why not keep adding more and more nutrients? Doesn't more equal better? No, nutrients are more like a multivitamin than food. After your plant has enough nutrients, adding more gives you diminishing returns, and too much starts causing the following problems.
Too high levels of nutrients causes...
- Nutrient burn - nutrient burn causes tips of leaves and edges of buds to appear burned. It isn't a huge deal but doesn't look as pretty, especially if it gets bad enough to spread to your buds.
- Random nutrient deficiencies and lockout
- Buds don't grow as big as they could have in the flowering stage
- Too high levels of nutrients may cause buds to have an unpleasant "chemical" taste
Now that you understand everything you need to know about picking the right nutrient system, check out some supplements!
Learn About Cannabis Supplements:
Creating a nutrient system is more complicated than just adding "Nitrogen," "Phosphorus" and "Potassium" plus all the various micro-nutrients in certain ratios. There several different chemical compounds that provide each of these nutrients and they're not all equal.
For example the following compounds all contain Nitrogen (Nitrate) in a way that's available to plants: Calcium Nitrate, Cobalt Nitrate and Potassium Nitrate. No compound provides nitrogen by itself; they also provide other elements like calcium, cobalt and potassium. So it's important to pay attention to these other nutrients being added to make sure you end up with the right ratios in the end.
To make things even more complicated, different compounds can interact with each other. For example, the Nitrate Nitrogens like the ones listed above become more available to the plant if a tiny amount of Ammoniacal Nitrogen is added to the mix, but Ammoniacal Nitrogen isn't good by itself.
If you want to learn more about mixing plant nutrients, the Hydroponic Handbook has some great information on how to mix up chemical nutrients with a focus on making nutrients for hydroponic mediums like DWC or coco. The rest of the book is "meh" but the section about mixing nutrients really breaks it down better than any other source I've seen. It even includes the mathematical equations you need to make sure everything adds up and you're not getting unwanted reactions! At the time of this writing you can read it for free if you have an Amazon Prime account!
Another well-rated book called The Handbook of Plant Nutrition is partially available to read for free on Google Books (though unfortunately some sections are missing from the free preview). This is a really great book packed full of info about how different minerals affect plant growth. In fact, it's actually used in classrooms to teach about plant nutrition! Unfortunately the full version costs an arm and a leg. This is a good choice if you want to really learn the ins and outs of plant nutrition, backed up by science!
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