Not all plants want the same substrate in which to grow. Succulents, for example thrive in a sandy, well draining soil that does not retain a lot of water, and regular dirt from you back yard – in most cases – isn’t going to work very well.
Like succulents, cannabis also needs a soil with great drainage. On the other hand, a sandy, or clay, or rocky soil often will make it difficult for the cannabis plant to penetrate deep into the earth and build the kind of massive root systems that lead to massive yields.
Let’s take a look at the some of the ways we can ensure the best quality soil for our plants.
Cannabis particularly thrives in spongy soils that are easily penetrated by the roots. Sphagnum, or Peat moss, is a really great base ingredient for a cannabis soil. When you’re at the grow store or local flower nursery next time, take a look at the contents of the different brands and types of soil. Silty, loam is another great example of a cannabis friendly soil texture.
Drainage & Aeration
Drainage is a really important parameter for cannabis as well. The roots of the cannabis plant do not particularly like to sit in water for very long, so a soil mix that has high water retention and low drainage is a problem.
Remember that while the leaves use carbon dioxide, the roots of the cannabis plant need plenty off oxygen.
Lots of perlite in the soil mix is a great way to solve several problems at once. Perlite resists soil compaction while offering great drainage. Because of its high surface area, perlite also helps create a high humidity around the roots even as the soil starts to dry, without suffocating the roots. Too much perlite will cause the water to drain too quickly. 10L of perlite to 25L of potting soil high in peat moss is a great way to ensure proper drainage.
Some cultivators use vermiculite, or hydroton instead of or in addition to perlite to customize and optimize their soil and root zone.
Soils purchased from your local grow store are going to have a list of their ingredients on the back of the bag. The nutrient content will be displayed as three numbers, such as “8-8-8.” This represents that there are equal parts nitrogen, phosphorous, and potassium contained within the soil. Many brands will also give an EC and pH value for the soil as well.
Remember that the nutrient content of this soil will probably only be rich enough for the first few weeks of the plants life before you’ll need to start supplementing the spent nutrients with nutrients in a water solution. For this reason, soils with a balance between the three elements is a great choice.
Look for a soil with a pH range between 6,0-7,0. This is the range in which cannabis, in soil conditions, thrives. Also look for an EC value that is not too high! Some soils for certain flowers or plants might be too rich for cannabis and could burn your seedlings from the beginning, stunting growth or killing the plant entirely.
Bug-infested and Old Soil
Its smart to keep in mind that some grow stores sell through soil mixes a lot faster than others. Make sure to be careful how old the bag of soil you’re buying is. If its been sitting in the store for too long, it can become overly dry, it can harbor bugs or pathogens, and can cause problems in your cultivation that are just best avoided all together.
This is why most cultivators choose to purchase from reliable, and established cultivation equipment vendors.
Outdoor, In-ground Soil Prep
The Soil in your back yard may or may not be the best option for growing cannabis directly in the ground. For those so lucky as to be able to grow giant trees worth of cannabis in their backyards without fear of repercussion from local law enforcement or thieves, there are several ways you can take advantage of the soil that’s already there and amend it to fit the needs of cannabis.
In parts of Colorado, USA and in parts of Northern Spain, you often will find a lot of red clay. Red Clay is amazingly rich in humid acids and the best sorts of organic materials that your plants will absolutely love – but clay can also be very difficult for cannabis roots to penetrate.
An easy solution to this is to dig out a 0,5×0,5×0,5m square out of the clay, and replace it with a well draining, and easily penetrated soil mix. This will allow your plant to establish a strong root system, and as it gets to the clay walls, the thick roots will be able to tap into the delicious organic acids the clay has locked inside of it. The good stuff from the local clay will also bleed into the soil from rain and watering, enriching the soil mix.
By doing a bit of research to discover what sort of soil you might have in your backyard, you can make use of the resources already at your disposal, saving money and potentially adding a level of sustainability to your production.