When growing cannabis it is important that you choose the correct medium. Do not underestimate how important the growing medium is as it could make or break your crop.
Perlite
Perlite is the generic name for a naturally occurring siliceous rock. The main selling point of perlite is that it has the ability to hold up to six times its own weight in water meaning that its water retention ability is next to none.
Perlite is great to add to your growing medium to provide good water retention and aeration. However if you use a purely perlite medium during a hydroponic grow it is important to make sure you have a filter set up to catch all of the minute particles that will wash off from the perlite.
Perlite also has a tendency to grow algae however you should not be worried as algae poses no risk to the health of your plant. Unlike vermiculite it will not turn to mush after use and it can actually be reused as long as you dry it thoroughly in the sun.
Gravel
This is probably one of the most readily available growing mediums on the market, you will be able to buy it from any builders yard. Gravel has a reputation for providing good aeration for your root system while also showing a good ability to retain water meaning that this is one of the best growing mediums around.
You will want to try and source some ‘pea gravel’ which is aptly named as all the bits of gravel should be about the same size of a pea, this is the perfect size if you are planning on using gravel as your growing medium.
If you purchase your gravel from a reputable source then you should just be able to wash it throughly and it will be ready for use. After the first crop the gravel will need to be sterilized with a chlorine mixture to ensure their is no unwanted bacterial growth.
Vermiculite
Vermiculite is sourced from natural deposits of mica which is widely distributed and occurs in igneous, metamorphic and sedimentary regimes. When the mica is heated it increases its size 15 fold and leaves a lightweight finished product. The finished product is highly absorbant meaning that is often used as an addition to other growing mediums such as perlite.
As vermiculite is so absorbant it does mean that it has a tendency to grow mold and fungus due to the constant dampness.
Sand
Although it would not be my first choice, sand can be used successfully as a growing medium when growing hydroponically. However before you start growing with sand there are a few things you need to look out for. Firstly you need to make sure you use a coarse sand to aid with aeration, it will also have to have low levels of calcium present within the sand.
I wouldn’t recommend curating your own sand, instead just visit your local builders merchant where they should sell small bags of builders sand which is perfect
It is also worth noting that sand has a tendency to lead to a build up of salts which if left unchecked will damage your plants root system. To avoid this make sure you flush your plant before feeding it just to ensure any unwanted salts are not present in the growing medium at the time of feeding.
Soil
There are so many different soil mixes on the market that it is important to make sure you pick the one that’s perfect for your grow. You should aim for something similar to a mix consisting of 25% white peat, 30% black peat, 30% perlite, 10% vermicompost and 5% fertilisers.
Be sure to go to your local grow store and actually buy some branded soil. Getting it from places such as your back yard might save a bit of money in the short term but could massively affect your crop in the long run due to the introduction of unknown pests.
If you pick soil as your medium of choice you need to be aware of the presence of fertilisers in the mix. If you feed the plants within the first few weeks of growth you risk burning them as a result of the excess nutrients.
Another positive about using soil as your growing medium is that it has a very stable pH meaning that it is perfect for new growers who are not so well versed in the more scientific side of growing cannabis.
Coco
Another growing medium commonly used for cannabis is coco coir. Coco coir is a natural and renewable resource made from the husks of coconuts. It is known for its excellent water retention and air circulation, and it is also pH neutral, which makes it easier to work with than soil.
However, coco coir can be expensive and may require the use of additional nutrients to support the growth of your plants. It is important to carefully research and select a high-quality coco coir mix and to regularly test the nutrient levels to ensure optimal growth.
Hydro
Hydroponics is another option for growing cannabis. This method involves growing plants in a nutrient-rich water solution rather than soil. Hydroponics allows for precise control over the growing environment, including temperature, light, and nutrition.
However, it can be complex and requires a significant investment in equipment and setup. It is important to carefully research and select the appropriate hydroponics system and to regularly test and adjust the nutrient levels to ensure optimal growth.
Conclusion
Ultimately, the best growing medium for cannabis will depend on your personal preferences and goals. Whether you choose soil, coco coir, or hydroponics, it is important to carefully consider the pros and cons of each option and choose the one that best meets your needs.