Hydroponic Cannabis: The Hydroponic Weed Growing Guide

By WeedWeek Sep 26, 2020

Hydroponic cannabis is a fascinating and effective way to grow marijuana. There are many different ways to grow weed hydroponically, ranging from huge commercial operations to a simple garden in your closet. This article will explore the different to grow weed hydroponically, what some of the advantages are, and what you’ll need to get started on a hydroponic garden of your very own. 

What Is Hydroponic Cannabis?       

Hydroponic cannabis refers to plants that are grown in a nutrient-rich water solution instead of soil. Hydroponic cannabis can be grown in a variety of different ways, using mediums ranging from clay pellets to only air, or in deep water buckets or even with fish. But you will not find soil as part of any hydroponic grow. 

Differences Between Soil & Hydroponic Cannabis      

Soil is composed of organic materials found on the Earth’s surface, composed of decaying detritus (fallen leaves, insect and animal corpses, and so on). Plants, including cannabis sativa, naturally grow in soil. However, it is also possible to grow plants in widely differing mediums that involve no soil at all. These are hydroponic methods of growing. Rather than roots embedding themselves into soil as they search for and absorb nutrients, a hydroponic grow provides a nutrient-rich, water-based solution that is applied directly to roots, enabling more efficient uptake.

The Advantages Of Hydroponic Cannabis Growing     

Growing cannabis in soil has its advantages, but with hydro, plants can grow taller, grow faster and provide larger yields. In soil, the roots of plants must search for the nutrients they need for growth. With a hydroponic setup, the nutrients are much more easily available and accessible, allowing the plant to divert more energy into stem, leaf and flower growth.

How To Grow Hydroponic Marijuana       

Growing hydroponic marijuana requires a bit more of a setup than a simple pot on your balcony. There are many hydroponic systems available that can suit any need  – from beginner to more professional. The Viagrow Complete Ebb & Flow Hydroponics System comes with a table, space for 14 plants and an automated delivery system for water, nutrients and oxygen. More simpler kids, such as the Deep Water Culture Hydroponic Bucket is easy to use and includes water level indicators, rockwool starter plugs and an air pump. 

But you can also go the do-it-yourself route which, although initially a bit more intensive to set up, can allow you to tailor your setup to your personal needs. 

    Equipment Needed   

Royal Queen Seeds provides the following list of equipment you’ll need for a do-it-yourself setup. 

  1. Seeds
  2. Grow tent
  3. Hydroponic reservoir and tray
  4. Lighting
  5. Lighting hangars
  6. Growing medium (more on this below)
  7. Hydroponic nutrients
  8. Pump and airstone
  9. Net mesh planting pots
  10. Carbon filter
  11. Duct tubes and ventilation fan
  12. Oscillating fan
  13. Hygrometer
  14. pH and PPM meters

    Choose A Growing Medium   

There are many options to choose from with regards to growing mediums. Below are a few of the most popular. 


Plant roots are meant to be submerged in soil, however, they can also grow in the air. With air grows, roots are misted with water and nutrients, which allows for plenty of oxygen and no drainage issues. The one danger is that the plants are utterly reliant on you paying close attention or, if you’ve got an automated grow, the power staying on – an outage could cost you your plants. 

        Clay Pebbles

Clay pebbles are porous, speckled pieces of clay that resemble dog kibble. Clay pebbles are perfect for delivering high quantities of oxygen for roots, retaining high amounts of nutrients and water, and allow for drainage as well. 

        Coco Coir

As the name suggests, coco coir is ground-up husks of coconuts, and are an increasingly popular choice for hydro grows. A coconut husk is designed to protect the inner flesh from harsh external factors and, most importantly, serves as a perfect germinating medium for a new coconut tree. Coco coir provides all of these benefits to your marijuana plants.  


Perlite is volcanic glass that has been infused with air, creating a porous material with high oxygen retention capabilities. Perlite is often added to soil mediums to boost aeration levels. This material is a great solution for hydroponic grows, although pay extra attention to water levels since perlite retains no water whatsoever. 


Rockwool is material made from melted rock fibers, similar to that of fibreglass. Although this material has been around for a long time, it comes with some downsides, including potential health hazards associated with inhaling dust from dried rockwool (the solution being to immediately drench the rockwool in water). Rockwool also comes with a relatively high pH that must be balanced. On the plus side, rockwool is an excellent water retainer.


Vermiculite has a pebble-like texture that retains water well, capable of drawing water and nutrients upwards (also known as “wicking”). While it can be expensive and can sometimes hold too much water, vermiculite is great for using in combination with other grow mediums, enabling you to tailor your medium to your specific setup. 

    Choose The Right Hydroponic Grow System   

Choosing the right hydroponic growing system is an important step. Be sure to take into consideration your level of expertise, how much money and time you’re willing to spend, and how many plants you’d like to include in your garden. Below are a selection of the most popular hydroponic grow systems to consider. 


In an aeroponic grow, no growth medium is used, allowing the roots to hang free. The nutrient solution is delivered via an aerosolized spray, creating a nourishing mist for the roots. The advantage to this misting technique is that it helps with nutrient absorption and uptake, which translates into bigger, faster plant growth. 


If you were one of those kids who had an aquarium in your room, you were halfway to an aquaponic grow without even knowing it. Plant roots are submerged into a tank of water that also contains living fish. As a closed-loop system, nutrients for the plants are not added in – rather, they are produced by the fish themselves as waste. As the plants absorb the fish waste, they in turn purify the water in which the fish live. 

        Deep Water Culture

A characteristic feature of a deep water culture hydroponic grow is the reservoir that can hold a large amount of water. Bigger volumes of water help enable a more stable nutrient solution, releasing you from the duty of watching nutrient levels on a continual basis. A deep water culture requires most of the root mass be submerged in water all of the time. Overall, this method promotes fast plant growth and is relatively easy to set up. 

        Drip System

Using a soilless medium, a drip system uses the popular irrigation technique of nutrient delivery via drip emitters, which mimic a light rain. There is generally one drip emitter per plant, delivering nutrients directly to the roots. 

        Ebb & Flood

The ebb and flood method uses a coarse growth medium, allowing roots to grow relatively freely with plenty of space and oxygen, increasing growth and yields. The nutrient solution is flooded over the roots, saturating the medium, while the reservoir is placed on a lower level which allows the solution to then flow back to the reservoir. This flooding needs to be done three times a day, which is why automated systems are a preferred choice for the ebb and flood method. 

Aerated Solution

The aerated solution method is similar to the ebb and flood method but recommended for those who aren’t using an automated flooding system and who can’t be available to flood three times per day. Rather than a reservoir, the aerated solution uses an aquarium aerator, making it possible to aerate the medium and provide a constant fresh supply of nutrient solution. 

        Nutrient Film Technique (NFT)

What makes the nutrient film technique stand out is that it doesn’t use a growth medium, allowing plant roots to grow extensively. Roots are constantly exposed to the nutrient solution via a fast-flowing, aerated currents, providing continual nourishment and oxygen. This method is ideal for larger-scale commercial grows.


Nutrients For Hydroponic Cannabis       

When looking for nutrients for your hydroponic cannabis, it’s important to select products that are tailored specifically for hydroponic grows. Do not use nutrients made for soil (products made of organic materials like guano or blood meal) because these nutrients can upset the delicate balance of the reservoir and potentially cause problems with the roots.  

Hydroponic nutrients are those provided by minerals that have been “chelated”, meaning they are rendered easier for plant roots to absorb. You’ll want to use nutrients with a proper nitrogen-phosphorus-potassium balance – look for a 2-1-6 balance on the label. Aside from NPK, check for sulfur, iron, magnesium and calcium for optimal results.

The Cost Of Growing With Hydroponics       

Costs of growing with hydroponics will vary based on your setup. Some factors to consider are electricity (which will vary based on the type and strength of your lights), space rental (which can be your closet or somewhere in your current living situation to cut down on costs), water, nutrients and CO2, and additional materials you might require, such as pesticides. One estimate puts a nine-week crop (meaning more than one plant, and bringing plants from seed to harvest)  at around $3500.

The History Of Hydroponics       

With all the trappings of modern technology, hydroponics may seem to be a relatively recent innovation. In fact, the opposite is true. People were growing plants hydroponically as early as 600 BC, in the famed Hanging Gardens of Babylon. These gardens were developed in response to dry, arid climates, where plants were watered using an irrigation-type system with water from the Euphrates River. The Aztecs in Mexico were also using hydroponic systems during the 10th and 11th centuries CE, as was China in the  late 13th century. 


In many ways, growing hydroponic cannabis is a superior method to growing in soil. Although there is a bit of a learning curve and sometimes a financial investment in order to get a hydro garden up and running, hydroponic marijuana can wind up producing a bigger, better harvest. It’s no wonder that, with a history dating back thousands of years, hydroponic is a preferred choice for many pot growers around the world.