Best hydroponic nutrients

We've researched all the options and compiled this short list of the best hydroponic nutrients for growing weed. This article will also teach you what nutrients your hydro plants need to grow big buds!  

Read our article on how hydroponics works (with infographics) to understand all the different hydroponic systems and their advantages.

Table of contents

Product comparison table

Click the product links below to read our detailed reviews.

Product Description Image Buy
General Hydroponics Flora Series General Hydroponics Flora Series Amazon
FoxFarm Nutrient Trio Hydro Formula FoxFarm Nutrient Trio Hydro Formula Amazon
Canna Coco Canna Coco Amazon


Reviews of the best hydroponic nutrients

General Hydroponics Flora Series

General Hydroponics Flora Series

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The best hydroponic nutrients for growing weed are the General Hydroponics Flora Series. The kit consists of 3 separate solutions called Grow, Bloom and Micro. GH products have such a good reputation that NASA use them in their horticulture experiments! Only use half what the bottles suggest and apply every time you water your plants. You can buy them in gallon, pint or quart bottles.

  • Gro is used during the vegetative stage
  • Micro is used during both stages
  • Bloom is used during the flowering stage to produce lots of buds

If you’re using a water based hydro setup, General Hydroponics even have a tool that lets you create a feeding chart!

FoxFarm Nutrient Trio Hydro Formula

FoxFarm Nutrient Trio Hydro Formula

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FoxFarm nutrients also have an excellent reputation and offer an excellent 3 part hydro nutrient solution.

  • Grow Big is used during the vegetative stage
  • Tiger Bloom is used during the flower stage
  • Big Bloom is used during both the vegetative and flowering stages

They have a useful feeding schedule chart here.

Canna Coco

Canna Coco

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We know a lot of growers love growing in Coco. If that’s you, the best hydroponic nutrients are from Canna Coco. Their Coco system has 2 parts for the vegetative and flowering stages and is specifically designed to work with coco mediums.  It also contains compounds to maximize absorption of the nutrients.

  • Coco A is used during the vegetative stage
  • Coca B is used during the flowering stage

They also have a useful grow guide on their website.

What is hydroponic growing?

Ebb & Flow system
Ebb & Flow hydroponics system

Hydroponics refers to growing plants in anything that isn’t soil. Most people think of hydroponics as growing in a water bath, but hydroponics also includes growing your plants in pots or containers using inert growth mediums such as coco, perlite and vermiculite.

Soil contains a lot of the nutrients your plants need to grow. When you grow hydroponically, your plants get no nutrients from soil and you have feed them everything they need to grow. If you’re growing in a water bath style hydroponic system you add nutrients directly to the water supply. If you’re growing in pots you can add nutrients when you hand water your plants.

There are a number of advantages to growing hydroponically:

  • It’s quicker - your plants can grow much faster during the vegetative stage of growth
  • You have complete control of the nutrients you give your plants and it’s easier to treat problems by changing the composition of the nutrient mix
  • Hydroponic systems (especially water bath based systems) can be easily automated for hands free growing

What nutrients do my hydro plants need?

All plants need 3 important nutrients to grow:

  • Nitrogen (N)
  • Phosphorous (P)
  • Potassium (K)

Together, these are known as the N-P-K scale. Your plants need different levels of N-P-K at different points in the growth cycle.

NPK levels during vegetative and flowers stages

All the best hydro nutrients for cannabis come with separate solutions containing the correct N-P-K ratios for each stage of growth.


  • Important for photosynthesis, the chemical process where plants use energy from sunlight to make sugars that power growth
  • Nitrogen helps your plants grow lots of leaves during the vegetative stage
  • Nitrogen needs to be removed during the flowering stage so your plants don’t waste energy producing leaves when they should be growing buds


  • Important in plant energy production and also plays a key role in developing roots and flowers.
  • Your plants need phosphorus to grow lots of buds during the flowering stage


  • Helps control how your plants burn energy and also allows your plants to survive periods of stress from lack of other nutrients or too little or too much water and sun
  • You plants need potassium to grow bigger, fatter buds

Other nutrients

In addition to N-P-K, there are a lot of other trace nutrients your plants need that would normally be found in the soil. These will all be part of the best hydroponic nutrients for growing weed. There isn’t a consistent recommendation on how much of these trace nutrients plants need so different brands contain different concentrations. Wikipedia has a complete list of all the nutrients plants need to grow if you want to learn more. Some of the main ones include:

  • Calcium
  • Magnesium
  • Sulphur
  • Iron
  • Zinc
  • Copper
  • Chlorine

How does the N-P-K scale work?

When you look at the bottles of hydroponic nutrients, the N-P-K scale is represented by 3 numbers. These 3 numbers represent the percentage by weight in the bottle of N-P-K.

For example, an N-P-K of 10-20-10 means that it contains 10% Nitrogen, 20% Phosphorous and 10% Potassium.

The rest of the bottle is composed of the other minor nutrients listed above, and filler so that you can spread the nutrients across many plants.

Generally speaking, we recommending using about half the dose that the manufacturers suggest. You plants will get more than enough nutrients and your supply will last twice as long.

How can I tell if my plants are missing nutrients?

  • You can spot low Nitrogen if your leaves look yellow
  • If your plants aren’t getting enough Phosphorous, they’ll be small, weak looking and produce tiny buds
  • Yellow leaves, curling up of the tips of the leaves and tiny buds can be signs of low potassium




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