There are various types of hydroponic setups used for growing cannabis. Some systems hold plants in pots filled with a hydroponic growing medium such as clay pebbles, perlite, or rockwool, with drippers dispensing water and nutrients to your cannabis.
Now, let’s take a look at the differences between each growing medium.
In conclusion, there is really no “best” growing medium for your cannabis—each has its own strengths and weaknesses. Many times, it will come down to cost, in which case soil is still the reigning champion.
• The Home Grower’s Guide To The Best Soil For Cannabis Choosing The Best Soil For Cannabis: A Home Grower’s Guide.
A growing medium is where your cannabis plants develop their root system. Many growers keep it simple with pots of soil, but you can also use coco coir, perlite, rockwool, or go for a fully fledged hydroponic setup.
What is the best medium to use for your cannabis grow operation? Find out the pros and cons of growing cannabis in soil, coco, rockwool, and hydroponics.
As a coco/perlite mix does not contain any nutrients, you are responsible for giving hydroponic nutrients from the start. The big advantage here is that you have full control, and your plants will grow as fast as in hydro. Downside: Just as with hydroponics, you will have to closely watch your pH levels. It’s also less forgiving of mistakes than soil.
Just like coir and rockwool, this is a reusable soil – again, you will have to clean it thoroughly after each use – and is only recommended for experienced cannabis growers.
As you can see, most soil mixes include fertilisers by default, this is why you shouldn’t feed your plants for at least the first two weeks of growing. Otherwise, you risk overfertilising them and eventually burning them. The good thing about growing in soil is that it acts as a buffer (the elements it contains are assimilated more slowly) and thus gives you a larger margin of error. Also, the pH is much more stable than in other growing mediums. Therefore, we strongly recommend going for soil if you are a beginner, as it is a reliable medium that will help you obtain the best quality crop.
Requiring no growing medium, aeroponics is also a great way to preserve the environment, as no waste material is produced. Also, you will need smaller quantities of nutrient solution as it is directly applied to the roots. There are high pressure and low pressure aeroponics systems. Cheap and easy to install, the former are the most widespread, whereas the latter are more efficient but also harder to use, requiring greater experience.
Expanded clay granules
The main difference is that with high pressure the nutrient solution is atomized more efficiently into a mist with very small droplet size, which allows the plants to make better use of it.
Below is the composition of most soil mixes available on the market (percentages may vary slightly across manufactures):
With more and more products now on the market, choosing a good soil mix is definitely not an easy task. A good starting point is considering things like permeability and aeration, as this will provide for the overall well-being of your plants. The main role of this type of growing medium is boosting the health and the development of the root system, whose function is comparable to the function of our digestive system.
With a pH of about 7, this inert substrate requires pH adjustment before use. To do so, you will need to leave the rocks to soak in a solution with a pH of 5.5 and an EC of 0.5-0.6 for 24 hours, after which you will be able to sow your seeds. The pH and EC levels of the nutrient solution for rockwool are the same as for coir and require constant monitoring as well, so we recommend this medium only to growers with some experience in hydroponics.
Each growing medium that you can use has different care and watering requirements.
Example of Great Soil – Fox Farm Ocean Forest is rich and light, plus it’s packed with nutrients in the right ratio for growing cannabis!
I have personally found coco/perlite to be the most straightforward and forgiving growing medium for indoor cannabis, and over the years I’ve also seen that coco growers seem to be the least likely to run into problems during their first grow!
Common Cannabis-Friendly Soil Mixes in the US:
When people are talking about hydroponics, they’re usually referring to growing your cannabis with the roots sitting directly in water. The most popular style of hydroponics for cannabis plants is known as Deep Water Culture (a.k.a. DWC), and it has a very popular variant known as “bubbleponics” or a top-fed Deep Water Culture (DWC) system.
If you decide to grow cannabis with soil, try using sterilized, loose, non-peat based potting compost. Often these are listed as an “organic potting mix.” I recommend soil mixes with at least 20-30% of a soil conditioner like perlite (little white rocks in the soil). This will provide drainage and keep higher amounts of air/oxygen in the soil, which causes cannabis plants to grow faster.
Good cannabis soil naturally contains at least some amount of nutrients, which means it will provide the nutrients your plants need for at least the first few weeks of life.
Even when it comes to soil mixes, you still often see both coco and perlite in the ingredient list, because they help improve the overall properties of the soil.