Biodiversity is the key when it comes to building a proper organic medium. Soil life thrives on diversity. That being said, there are a few things to keep in mind with building a soil that caters to growing cannabis.
How to Amend Organic Soil
An organic soil can be amended with only a handful of ingredients, such as the following:
- An organic base material such as peat moss or coco coir
- An aerating agent such as perlite or vermiculite
There are many variations to this sample amendment, and picking the right one will depend on what your plants require. For instance, many choose to use vermicompost (worm castings) for their super soil. Subcool from TGA Genetics starts his recipe by incorporating a base potting mix (in his case, Roots Organics potting mix) containing coco, peat, perlite, worm castings, bat guano, and more. He then amends this mix with a handful of other beneficial organics in order to boost biodiversity while also providing key nutrients resources for cannabis.
You don’t have to start with a pre-made potting mix to make a successful super soil . Simply divide your favourite compost, base, and aerator into equal parts and mix together to form your initial starting point. You will, however want to consider adding a few more goodies to the pot before calling it a day.
1. Begin With Your Base Mix
Combine equal parts compost, organic material, and aeration. How much you begin with will depend on your needs. Consider that this base will account for approximately 20% of the total volume of your mix.
One popular formulation of this recipe that works well is:
- 1 part compost of your choice
- 1 part coco coir and/or peat moss
- 1 part perlite
2. Establish a Fungal Population
A diverse microbiology in your soil will be contingent on many factors, and establishing food to grow a healthy fungal population is one of the most important. Fungi love to develop mycorrhizal relationships with root systems (or rhizosphere), and providing food for them to thrive will help facilitate these tiny little symbiotic friendships.
The result? Friends always like to bring food to the party. Picture your cannabis as the partygoers—they like food!
Here are some terrific amendments to build fungal life:
- Kelp meal: 1/4 cup per 5 gallons
- Humic acid: 1/4 cup per 5 gallons
- Mycorrhizal inoculant (endomycorrhizae powder): 1/4- 1/2 tsp per gallon
3. Establish a Bacterial Population
Just as important as fungi, bacterial populations can help break down complex sugars and convert them to readily available macro and micronutrients for your cannabis. They also help to establish and maintain the immune system of your plants, making them more adept to fight off pests, diseases, and inclement environmental conditions.
These ingredients help bring the bacteria:
- Vermicompost (worm castings): up to 20% total substrate
- Bat Guano: up to 5% total substrate
4. Fortify With Micro and Macronutrient Sources
Cannabis, like any other plant, requires a regiment of micro and macronutrients to thrive. In many case, these nutrients are often provided via plant fertilizers. However, with organic super soils they’re instead amended into the base mix to be released and/or broken down into food for your plants over time.
Here, we covered how to find the right soil amendments, but here’s a brief refresher of popular soil amendments to add and their respective nutrient contents:
- Blood meal (nitrogen)
- Bone meal (phospherus, calcium)
- Rock phosphate (phospherous)
- Epsom salts (magnesium)
- Crustacean meal (nitrogen, phosphorous, calcium, magnesium)
- Dolomite Lime (pH balance, magnesium)
- Azomite (micronutrients)
- Wood ash/bio char (potassium)
Keep in mind that there are many ways to amend a super soil, including various methods to concocting the aforementioned recipe. Building a successful organic soil is, in many cases, a trial and error endeavor for the home grower. Subcool himself admits to changing his recipe (albeit very minutely) each year to adapt to the needs of his plants.
Be sure to experiment to your cannabis plant’s liking when mixing your soil, and never be afraid to change things up a bit in the process. Your crop will thank you for it in abundant yields and immaculate flavour!