I’ve received a number of requests for the living soil mix I use personally. While I have published a general DIY Soil Mix, there are a few adjustments in what you will find below. I did not invent this mix and refuse to take credit. Modern potting soil mixes are based on the ‘Cornell Mix’ developed by Cornell University researchers in the mid-twentieth century. It was later fine tuned for cannabis by Clackamas Coot (use search term “Coot Soil Mix”). This mix is largely Coot’s mix with just a couple adjustments.
1 cubic foot recipe
2.5 gallons peat moss*
2.5 gallons aeration material**
2.5 gallons compost or worm castings
0.5 gallons biochar
Minerals:
1/2 cup oyster shell flour***
1/8 cup crushed basalt
1/8 cup green sand
1/8 cup azomite
Nutrients:
1/2 cup kelp meal
1/2 cup neem cake
1/2 cup crustacean meal
1/2 cup bone meal
1/4 cup insect frasssolid form of insect excrement; bug poop More
1/4 cup oatmeal
1/4 cup malted barley (ground)
<read more about using insect frass and grains as amendments>
Inoculate:
Bacillus Thurigensis-israeleus, Beauvaria Bassiana, & LABS****
Notes:
* Peat moss should be thoroughly hydrated prior to mixing for best results
** A variety of aeration materials may be used, including perlite, lava rocks, shale, pumice, rice hulls, etc.. If you plan to maintain a colony of red wiggler earth worms in your bed, rice hulls are an excellent choice. The rice hulls will eventually break down and the worms will take care of aeration on their own.
*** Peat moss is slightly acidic, so use of oyster shell flour or gypsum is needed to buffer PHa measure of the acidity or alkalinity of a solution More in the soil. Both are also good sources of calcium. Avoid using dolomitic lime as it may add too much magnesium to your mix.
**** Innoculations as described above are optional, but I highly recommend doing so. Compost often comes with a colony of fungus gnats and/or white flies – among other things. While these decomposers are generally good, they can become a problem indoors. It’s always best to start your pest management practices very, very early on. The LABSlactic acid bacteria serum More part of the inoculation is to boost your beneficial microbe counts. This can be accomplished with a quality compost/castings tea as well. The compost/casting used in the soil mix should do the trick, but I don’t mind taking it up a notch. If you water over the top then a top-dressing of compost or castings will also work well in the place of tea or LABSlactic acid bacteria serum More.
Be sure to let this mix sit for a week or two – depending on your conditions. After just a few days you can feel how [literally] hot the mix is by plunging your hand into the middle of it. You will need to wait until the mix cools off before use. I always have a batch of living soil ‘cooking.’ This mix is great for seedlings and clonessoft-tissue cutting of a cannabis plant. A misnomer. More provided the mix is well aged. During this period is also when the biochar gets charged with nutrients and microbe colonies.
Last but not least, this early decomposition process releases a great deal of CO2 into the environment which is a great secondary benefit.
Happy Harvests!
— The Lit Farmer —