Most water-only organic living soils on the market will cost the cultivator $20 per cubic foot or more, before shipping. I’ll share with you how to get this done for half that price, with a higher quality product. I don’t take
credit for these recipe’s as they were established many years ago by academics and refined over the years by experienced cultivators. What I can say for sure is that it is effective and grows some really high quality cannabis.
Dry Mix | Moist Mix | |
Peat | 1/3 | 1/2 |
Aeration | 1/3 | 1/4 |
Worm Castings | 1/3 | 1/4 |
Bio-char (% of total) | 10% | 10% |
Peat is commonly available and often comes in compressed bales which can expand up to twice the starting volume. You’ll want to get a nutrient pack designed for peat as it contains additions that moderate peat’s acidity.
Aeration is important and, while perlite is the most commonly used aerator, it tend to be light enough to literally float to the top of your mix. You can also use pumice (my preferred), lava rock, or even hydrotons (little clay balls). Stay away from gravel that may contain too much calcium.
Compost can be substituted with worm castings and are the magic component of a good soil mix. A good compost and raw worm castings are full of the microbial activity that we need in our living soils. As long as it’s well aged compost it also makes a good top dressing.
Bio-char can be difficult to source at times and might also be the most expensive component of this mix. However, I believe it is a key to making your soils tolerant to abuse and encourages long life at full production. The Amazonians developed it long ago, so why wouldn’t you? Add this amendment based on your total soil volume. 10% is good, 15% might be a little better, but 20% is too much. Example: If you just mixed 10 cubic feet of soil, add 1 to 1.5 cubic feet of bio-char.
Nutrients & Minerals
You can mix your own nutrients as well, but it may be more fool-proof to buy some pre-mixed. One of my all-time favorites is Coot’s Mix. I’ve followed his work for a long time. These nutrients are essential to making your soil ‘water-only.’ This means that you will only keep it watered and will NOT need additional bottled nutrients and so forth.
Note 1: It is crucial to properly hydrate your newly mixed soil and will take more water than you expect. You should get the soil to field capacityThis refers to the water content of soil. The easiest way to... More in order to properly activate the microbial life and make it possible for it to break the nutrients down into plant usable forms.
Note 3: Water your soil even if no plants are in it. In order for the microbes to do their work they need that field capacityThis refers to the water content of soil. The easiest way to... More soil to operate in. Letting the soil go dry will kill some microbes and force others into hibernation. I like to put a cover crop on it when not in use otherwise.
Note 2: Once you have your ingredients mixed you will need to let it ‘cook’. After a few days, put your hand in the pile – it will probably feel warm. If it is noticeably warm inside, re-hydrate to field capacityThis refers to the water content of soil. The easiest way to... More, remix the pile, and wait a few more days. Repeat until the pile cools off. Check the temperature before you add water. Pro-tip: the more nutrients you add, the long it takes to cook.
Let us know how your custom built soil works out, or what improvements you might have.
Happy Harvests!
–The Lit Farmer–