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A big decision when starting to grow your own cannabis is whether to grow in soil or hydroponics. Hydroponic cannabis refers to cannabis that is grown without the use of soil. Instead of the natural nutrients found in soil, growers will apply their own nutrients throughout the grow process. There are many advantages of growing in hydro such as less risk of attracting pests, faster growth and can often produce higher yields. 

Hydroponics also comes with risks such as root damage if there is a power failure or if you run out of water. Hydroponics also requires more maintenance as there are many more things that can go wrong than with a soil grow. This is why it is important to start with one of the simpler systems as a beginner such as a Deep Water Culture System.

Despite the extra care involved with hydroponics, it still offers growers far more control over the nutrients that go into the plant and allows the water that is not absorbed by the plants to be recycled back into the system which can save you on water.

If you have chosen to grow your cannabis in a hydroponic system, this guide will help you get started.

 

Deciding on A Hydroponic System

There are 6 systems below. We recommend you take some time to read about each one.

There are a few factors that should influence your decision; the amount of space you have available, the amount of plants you want to grow, and finally - your budget. It is recommended to start small when learning and expand later as it can get very overwhelming with too many plants. 

Deep water culture (DWC) is a great place to start for beginners as it is usually the cheapest option and most simple to use.

Choose A Light Source

Light is one of the most important factors when growing cannabis. You will need a powerful light source to get the most out of your hydroponic cannabis grow. There are many different types of grow lights each with their own advantages and disadvantages.

When choosing a grow light consider the units cost, the intensity of the light, which light spectrum it emits, and how much area coverage you will need. 

If you do not have the adequate space available indoors, consider positioning your hydroponic system outside in an area that offers a fair amount of direct sunlight.

 

What Growing Media?

When growing in hydroponics you will need a soilless growing medium. A growing medium is the substance that will hold the plant stem and roots in place. There are many different types of growing medium available. Each with their own unique benefits and some work better than others in certain hydroponic systems. Here is a list of the most common types of grow medium used by cannabis growers.

 

LECA (Lightweight Expanded Clay Aggregate)

These clay pebbles are a popular option when it comes to hydroponics. They are created by heating and expanding clays to from thousands of small bubble shaped balls.

These pH neutral and sterile clay pebbles provide excellent oxygenation for the roots. The roots are not placed under any stress and grow easily, which makes nutrient absorption very efficient. 

This clay aggregate is porous enough to give it some good water-holding ability, though not sufficient for systems using a single daily watering. Rather, this medium is better suited for continuous-flow or multiple-watering hydro systems.

 

 

Rockwool

This sterile, porous medium is spun from fibres created by melting various rock types, these fibres are then pressed into various plugs, squares, and slabs for growing plants. 

Rockwool has a great capacity to retain water, which allows for good hydration of the upper root system. This protects the plant from dehydration while providing the plant roots with a continuous amount of oxygen. 

Rockwool has a generally high pH, so it is recommended to soak this media in pH balanced water before use.

 

   

Perlite

Perlite is a volcanic glass that expands when exposed to high temperatures. It is very lightweight and porous which is why it is often mixed with other growing media such as vermiculite, coco coir or soil to provide aeration. 

 

   

    

 

 

 Coco Coir

 Coco coir is essentially the by-product of the coconut industry. It is made from the brown husks around the coconut shell. It is completely organic, highly inert and holds water very well.

   

   

   

    

Get Your Nutrients

The three most essential minerals for growth are nitrogen (N), phosphate (P) and potassium (K). Just like humans, your cannabis plants will need nutrients to grow strong and healthy.

Some nutrients are made for soil and others are made specifically for hydroponics. When purchasing nutrients, you should always check that they are compatible with the growing medium you have chosen.

 

Prepare Your System

Once you have chosen your hydroponic system, the growing media you will be using and bought your nutrients, it is time to set your system up. 

Before you run your system make sure all your equipment is clean and wipe down all buckets, trays and pipes to prevent any contamination.

Once your system is clean, set it up and make sure everything is working and running smoothly.

 

Ready, Set, Grow!

You are now ready to plant your germinated seedlings into their new home to grow and flourish.

 

Maintaining Your System

Remember that every hydroponic system requires frequent maintenance to provide your plants with an optimal growing environment. Here are some factors you need to be aware of.

 

1. Always monitor pH

You will need to constantly test the pH of the water to ensure an optimal environment. Nutrients are more available to your plants when the environment is slightly more acidic.  The pH of your water should therefore be between 5.5 -5.8. 

You can use a pH testing kit to take regular readings and change the solution to maintain this range.

 

2. Water temperature

The ideal temperature of hydroponic cannabis is 20°C. Always try to keep your water to around this temperature. You can monitor this by using a water thermometer. If the water is too cold you can use a water heater to increase the temperature.

 

3. Provide the correct quantity of nutrients

Just like soil-based plants, hydroponic plants also require nutrients. You will need to purchase nutrients made for hydroponics that contain all the required minerals needed for both vegetation and flowering stages. The product will usually come with instructions on how often to add nutrients into your system as well as how much dilution is required.

 

4. Keep your system clean

The water in the reservoir should be changed out once the volume of added top-off water equals the total volume of the tank, usually around every two to three weeks. This prevents the over-accumulation of nutrients, bacteria, and fungi. Depending on your system you may change it more or less often to maintain optimal pH and nutrient levels.

 

5. Choosing a strain for hydroponic growing

Strain selection is very important when it comes to hydroponic growing. Plants grown in these systems are free to take in nutrients extremely fast, which often results in rapid growth. Therefore, selecting a large sativa variety is not the best choice, especially if your system is in an indoor tent.

 

Smaller and more compact strains are better suited for indoor hydroponic systems. Starting with a smaller strain is advantageous for a few reasons:

• You will be able to cultivate more plants within a smaller space, allowing for more diversity and potentially bigger yields.
• If your plant does go through a growth spurt, you will have the space to deal with the sudden height.

 

Some Final Notes on Growing Cannabis in Hydroponics

Hydroponics can seem very intimidating and complicated to beginners. All the different systems, parts and methods can be overwhelming. The key is to start out simple, choose an appropriate strain and always keep track of your plant’s environment daily for any complications such as pesky pests or plant disease. Check your leaves regularly for any unusual discolouration, keep your reservoir topped-up and well oxygenated and most importantly have fun growing and enjoy the fruits of your labour.