Best Hydroponic Nutrients for Cannabis?

Updated Jan 05, 2021

by Nebula Haze

What makes hydroponic nutrients “good” or “bad?”

In other words, why are some hydro nutrients better than others for growing cannabis? What kind of hydroponic nutrients need to be avoided when growing marijuana? Do you need expensive nutrients to get good results, or will cheap nutrients get the job done?

With all the different bottles of marijuana nutrients out there, how do you know which one is best for your hydroponic setup?

Example of a complete hydroponic nutrient lineup - in this case it's the entire General Hydroponics Flora trio nutrient system

When it comes to choosing hydroponic nutrients for growing weed, there are a few considerations that are really important!

Example of two happy cannabis plants growing in a hydroponic DWC reservoir with suitable hydroponic nutrients!

Best Hydroponic Nutrients

  • Made specifically for hydroponics
  • No organic matter (nutrients are provided via minerals)
  • Mineral nutrients are “chelated” (easier for plant to absorb at a greater range of pH levels)
  • Contains rich sources of micro-nutrients (to make up for what might have been found in the soil)
  • Optimum NPK ratios (more info below)

Worst Hydroponic Nutrients

  • Made specifically for soil
  • Contains a lot of organic matter (guano, worm castings, fish emulsion, blood meal, etc) – this stuff can completely mess up your reservoir and cause unexpected and unwanted bacteria/root problems. If it seems cloudy with lots of material floating in the water, don’t use it for hydro!

You can learn a lot about nutrients by looking at the label!

Example of looking at the back of a cannabis nutrient bottle to learn more about the ingredients and the ratio of nutrients to each other

Optimum NPK Ratios for Hydroponic Cannabis Nutrients

N-P-K stands for Nitrogen-Phosphorus-Potassium, which are the three most important plant nutrients. These are what the 3 numbers listed on the front of all nutrient bottles stand for (Potassium is represented by “K” because chemists use the symbol K in the periodic table for potassium).

In order to get the best results growing cannabis in hydroponics, it’s important to give the right ratio of these crucial nutrients so the plant gets what it needs at the right time. For example, if you give too much Nitrogen in the flowering/budding phase, it actually surpresses bud production and reduces your yields even if the plant is completely healthy! You don’t want that!

So what are the optimum NPK values for growing cannabis in hydro?
(N-P-K are the 3 numbers on the front of nutrient bottles)

Most cannabis nutrient bottles prominently display 3 numbers, called "NPK" which stands for Nitrogen, Phosphorus and Potassium. These numbers tell you the ratio between each of these nutrients in the bottle

Optimal Hydroponic Cannabis N-P-K Nutrient Ratios
Life StageNPK
Vegetative/GrowHighMedium to HighHigh

Additionally, hydroponic nutrients should always include….

  • Magnesium
  • Calcium
  • Iron
  • Sulfur

Nice but not necessary micro-nutrients (contained in most water sources, but if using RO or very soft water you want these in your nutrients to prevent possible deficiencies)

  • Boron
  • Cobalt
  • Copper
  • Manganese
  • Molybdenum
  • Zinc

The main difference between NPK ratios for hydro and soil are….

  • Hydro nutrients usually contain more micro-nutrients (in trace amounts), to make up for what the plant would have been able to find in the soil
  • Hydro nutrients tend to contain higher levels of Nitrogen, which is abundant in soil but not in most water sources.
  • Hydro nutrients tend to have lower levels of Phosphorus, because Phosphorus is more “available” to the plant in a hydroponic setting. In soil, there are microorganisms (as well as clay “colloidal” particles) which can ‘steal’ some of it, and soil nutrients compensate by adding more Phosphorus.
  • Hydro nutrients rarely use organic sources of nutrients. Soil nutrients often contain organic material, which can can make it easier for bad stuff to grow in a hydroponic reservoir. Organic sources of minerals also usually need to be broken down by microorganisms before the plant can absorb them, which doesn’t happen as well in a soilless environment.
  • Hydro nutrients are often made up of chelated minerals which have been specially treated so they are easier for the plant to absorb.

What are Chelated Nutrients? Manufacturers actually “wrap” the nutrients inside an organic molecule that is less affected by pH, making it easier for the plant to absorb even if the pH is too high or too low.

When set up right with good nutrients, DWC / Hydroponics can produce some incredible yields!

This Master Kush plant in a DWC setup helps show what you can accomplish as far as yields in a hydroponic setup with good nutrients!

Optimum pH of 5.5-6.5 <—- Sooooo important in hydro

No matter which nutrient brand you’re using, even with chelated nutrients, cannabis roots are better able to absorb some chemical forms of nutrients than others. This is where pH comes into play. When the pH at the roots is too high or too low, it actually changes the chemical form of the individual nutrient compounds, making it more difficult for your plant to absorb the nutrients it needs.

With hydroponic cannabis nutrients, they’re designed to be most available to your plant when the pH is between 5.5-6.5. If you let the pH get higher or lower than this, you will start getting nutrient deficiencies even if literally everything else is dialed in!

Learn how to adjust your pH to prevent nutrient deficiencies
(It’s easy! It’s kind of like a supplement you add to your reservoir to get better growth)

Adjusting your pH only takes a few minutes, and your cannabis garden will thank you!

Stay skeptical of companies that say their nutrients will “automatically” adjust the pH of your water. Although some nutrient systems may be better than others at stabilizing pH, you still need to check the pH regularly if you want to get the best results in hydro. Seriously, this is really important!

Depending on your starting water, “PH Perfect” nutrient systems sometimes aren’t able to correct the pH to the right levels, at least not consistently throughout the grow.

This could happen for various reasons. For example your source water likely contains minerals and other “stuff” that will change the pH of your water. If you start with highly purified water instead of tap water, it can actually make pH swings worse because there is no “buffer” in pure water to stabilize pH.

Plus, the amount of nutrients you use changes depending on your plant and its stage of life, and changing the nutrient levels will almost always change the pH, too!

If you check the pH and it’s in the right range, that’s perfect and there’s nothing else you need to do. But don’t skip checking the pH just because the bottle says you don’t have to! Or at the very least, make sure pH is the first thing you check if you start seeing nutrient problems!

Recommended DWC Nutrients & Supplements

These hydroponic nutrients systems are not just great as far as cannabis yields and quality, they won’t break the bank either! There are lots of great nutrient systems out there, but the truth is that you don’t need incredibly expensive nutrients to get incredible marijuana!

The following nutrient systems have proven to thousands of growers, big and small, that they have everything needed to produce star-quality cannabis!

General Hydroponics Flora Trio Lineup

General Hydroponics Flora Series Nutrient Trio <– Recommended for Beginners.

This is the cannabis nutrient system I have been using to grow hydroponically for more than half a decade. General Hydroponics is a trusted nutrient company and their Flora Trio works very well for beginners and advanced cannabis growers.

One cool thing about the General Hydroponic Flora trio is it contains tons of micro-nutrients in trace amounts that often aren’t even found in other hydroponic nutrients. That makes this a great choice as a complete nutrient system for growers using RO (reverse osmosis) or very soft water that doesn’t naturally contain many common minerals. The GH Flora trio will work for just about any setup with just about any water.

Feel free to check out a grow journal where we pulled in over 20 ounces from a single 600W tent using just the Trio plus Hydroguard for the roots (pic below). We didn’t use anything else for the whole grow and were very happy with our results.

Here’s my custom DWC cannabis schedule for the GH Flora trio [PDF].

General Hydroponics Flora trio - includes all your base nutrients!PlusGeneral Hydroponics CaliMagic Cal-Mag supplement

Hydroguard (formally known as Aquashield) – prevents and treats root rot

Get Hydroguard on! ​

These plants grown using just the GH Trio + Hydroguard (formally known as Aquashield)
Feel free to check out the complete grow journal (over 1 lb harvest!)

A view of the cannabis grow tent - there is a blue lighter in the middle for added perspective


General Hydroponics Flora Duo Lineup

General Hydroponics FloraDuo (Bottle A & Bottle B) <– From a grower: “This is a great choice by GH if 3 bottles seems like too much to deal with. You have less complete control, but it can be a better way to get a “sense” of what the plants need at each stage, since you’re only using two bottles.” Another grower said: “Flora Duo are foundation tools in my eyes. If you’re new and you really want success early on, a simple line like the Flora Duo is going to be good. Less bottles to play with, super simple feeding schedule, and you learn. People pick up on the fact that bottle A is high nitrogen, you use a lot of it the first half then it switches to bottle B that has more Phosphorus and Potassium. So you gain some understanding as to WHY you need both, and what different things do for the plant.” Here’s the FloraDuo Nutrient Schedule from General Hydroponics [PDF]

 PlusGeneral Hydroponics CaliMagic Cal-Mag supplement

Hydroguard (formally known as Aquashield) – prevents and treats root rot.

Get Hydroguard on! ​


House & Garden DWC Kit Lineup

Warning: H&G Products have been difficult to find online lately

The House & Garden line-up is expensive yet remarkably effective. Aqua Flakes A + BRoots ExceluratorAlgen Extract <– Get a custom nutrient schedule directly from the people at House & Garden via their free online nutrient calculator.

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.”​

House & Garden Aqua Flakes A & B - these hydroponic cannabis nutrients work great - in fact they were even tested on real cannabis plants!House & Garden Roots Excelurator - a great root supplement for growing cannabis hydroponically House & Garden Algen extract - works great with the complete H&G lineup for growing cannabis hydroponically, in fact this supplement was even tested on real cannabis plants!

Hydroguard (formally known as Aquashield) – prevents and treats root rot. No need for extra Cal-Mag with the Aqua Flakes line as it already comes with plenty!

Get Hydroguard on! ​


Botanicare KIND Hydro Lineup

This is actually the hydroponic nutrient lineup I plan to use for my next grow. Right now I’m using the General Hydroponics Flora trio (which I’ve used for more than half a decade with amazing results), but I’ve decided I want to try something new and KIND is what I’ve decided to go with. I’ve heard/seen so many great things about it and Botanicare is a great company that takes feedback from cannabis growers and is happy to answer any questions if you contact them through their website.

Botanicare KIND Trio For Hydro (BaseGrowBloom) <– The three bottles are all that’s needed to get your plants successfully to harvest time, just follow the feeding schedule from Botanicare (here’s a PDF, here’s a JPG​) to start. They offer a lot of supplements, but the only bottles you need to be successful growing cannabis is the 3 listed (Base, Grow, Bloom), which is what’s reflected in the “standard” version of their schedule. Repeat “Week 3” of the Vegetative part of their schedule until the end of the vegetative stage if it lasts longer than 3 weeks.

Get KIND Nutrients from Amazon - good for growing cannabis hydroponically!  Get KIND nutrients for hydroponic marijuana - on Amazon!  Buy KIND nutrients on for your garden!


Hydroguard (formally known as Aquashield) – prevents and treats root rot.

Get Hydroguard on! ​PlusBotanicare Cal-Mag supplement - get it on Amazon!

From a grower who wrote in: “I use the Botanicare KIND lineup – it seems to get good results, not too expensive, and works very well in hydro.” Another grower told us, “As far as favorites go, I’ve been pretty pleased with Botanicare KIND, it’s ‘pretty good’ when you follow the chart, but once you start tinkering with it based on what you see with your plants, it’ll really shine since it was developed to be played with.” Apparently a lot of growers like tinkering with this trio as another grower said, “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 seakelp! 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.”


If you think you have the best hydroponic cannabis nutrients, tell us about your results!

More on Cannabis Grow Mediums…


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