Cannabis Science

Hydroponics Nutrients for Weed


If you’re considering growing your own cannabis at home, you might have considered using hydroponics. Hydroponics is just a fancy word that means growing plants without using soil. Instead of soil, you can opt for water, sand or gravel. You’ll have to add nutrients to these media to make sure your plant gets what it needs to grow and be healthy. It’s believed that it’s actually better to use a hydroponic system than soil when growing weed. We’ll be comparing hydroponics to soil, hydroponic nutrients for weed, and the best nutrients for weed. 

Photo: Pexels

Hydroponics vs Soil For Weed

According to Royal Queen Seeds, using hydroponics allows the grower to have more control over what the weed plant is absorbing. Royal Queen Seeds say that “[Weed grown using hydroponics] are not exposed to any chemicals you do not want to introduce to the environment. Cannabis is notoriously sensitive to heavy metals and other impurities in the soil.”

However, with hydroponics, you won’t have microbes that can convert things found in soil into helpful materials for the plant. That’s why the addition of nutrients comes in, but we’ll get into that later. 

Here is a list of why using hydroponics may be better for growing weed than soil, according to Royal Queen Seeds:

  • Less exposure to pests due to the closed off nature of hydroponics
  • You save water since there is no soil to absorb the water.
  • Less use of pesticides since there are less pests
  • Healthier plants since hydroponic grown weed has less diseases
  • Affordable
  • Creates higher yield
  • Weed seems to grow faster using hydroponics than soil

What Cannabis Growers Have to Say About Hydroponics

If you don’t take our word for it, maybe you’ll take it from people growing weed as a living.

Norfolk resident Matt French was quoted in a WTKR news article saying hydroponics was low maintenance and easy to set up. French also said that hydroponics is the best for high yields. He purchases his products from I Love Hydroponics. 

What are Hydroponics Nutrients?

As we mentioned before, you’ll have to provide nutrients to weed grown by hydroponics because there is no soil. Hydroponic nutrients refer to key nutrients that weed needs to grow and flourish. 

Using the correct nutrients is one piece of the puzzle. You’ll also need to make sure the pH is optimal for nutrient absorption. According to Royal Queen Seeds, “nutrients tend to be better absorbed when the pH around the root zone is between 5.5-6.5. But the ideal value you should aim for is 5.7.”

Coupled with the optimal pH, there are a couple of nutrients that are needed for optimal growth. These nutrients are broken down into macronutrients and micronutrients.

Best Hydroponics Nutrients For Weed

According to Royal Queen Seeds, marijuana will need the following nutrients to grow:

  • Nitrogen
  • Phosphorus
  • Potassium
  • Iron 
  • Copper
  • Magnesium

Nitrogen, phosphorus and potassium are macronutrients. Iron, copper, and magnesium are micronutrients. 

The table below shows the purpose of each nutrient and how to spot it when your weed plant is lacking them.

Nutrient Purpose Evidence of Deficiency
Nitrogen Leaf growth and pigmentationOlder leaves become yellow and soft
Phosphorus Development of stems, roots, and flowersDeficiency during the flowering stage will affect the quantity and quality of your buds
PotassiumDevelopment of the buds, stems, roots, and protein.Brown or yellow coloring in the tips and edges of the leaves
IronFormation of chlorophyll, maintenance of chloroplast structure and function.Yellowing of new leaves
Copper Enzymatic activities, chlorophyll, and seed production.The plant turns dark with blue or purple undertones or a shiny metallic appearance
The tips and edges of leaves will turn either a bright yellow or white.
Magnesium Helps with photosynthesis, metabolism of carbohydrates, and cell membrane stabilization. Bottom leaves will yellow and the tips will dry out and become brown and crunchy
Shoots will turn purple
Acceleration of leaf chlorosis
Sources: Royal Queen Seeds [1,2,3,4, 5] Jstage, Gardening Know How, UMN Extension

FYI There are many other nutrients but we covered the main ones.

Buying the Right Nutrient Solution for Weed 

The good news is, there are nutrient solutions out there that you can just buy. Cannabis has different needs during its growth and development. Therefore, you’ll need to pick different nutrient solutions based on that, as well as what it may be lacking. 

 According to Royal Seed Queens, consider these tips when buying nutrient solutions for weed:

  • Leave nutrient solutions that have organic matter alone. Otherwise, you may run into root issues and bacterial growth.
  • Opt for chelated minerals. This ensures that the plant can absorb nutrients in a wider range of pH.
  • Consider the nitrogen, phosphorus and potassium ratio. This will be in the form of a ratio on your product.
  • When your cannabis plant is in the vegetative state (the period of growth between germination and flowering), you’ll need to ensure there is lots of nitrogen, phosphorus and potassium. 
  • During the flowering stage, ensure the nutrient solution has low nitrogen levels but high phosphorus and potassium levels. 


Growing weed using hydroponics could be an excellent idea. There are tons of advantages such as having a higher yield and having fewer bugs. However, don’t forget to seek out the proper hydroponic nutrients for weed so that your plant can be healthy.


About Trevann

Trevann is Stoner Rotation’s Jamaica-based lead writer for the Science section of our cannabis blog. She graduated with honors receiving her Bachelor of Science degree in Molecular Biology from the University of West Indies, Mona. For the last three years, she has covered some of the biggest questions around cannabis and health underpinned with research from supporting studies, medical journals and scholarly articles. Got something on your mind? You can reach her at [email protected].