Our recipe is as simple as it gets: in a large plastic tub, mix together equal parts cow manure, raw vegetable/fruit waste, barley or wheat straw, wood chips, and shredded paper; let the mixture sit in for 28 days, stirring occasionally, and serve to your worms in small batches as needed.
Now this is worm food, not rocket fuel so when we say equal parts we mean equal-ish — eyeballing it is fine, there is no need for proper weights or measures, again, we are literally making worm food.
What is important however, is a diversity in ingredients. A diversity of decaying ingredients attracts a diversity of microorganisms, which is exactly what we want.
Moreover, certain ingredients select for (i.e. attract) specific types of organisms which can be used to create feedstocks with specific benefits. For example wood chips and shredded paper attract specific types of desirable fungi; as our farm (i.e. Prairie Son Acres) is still trying to develop strong fungal networks in our soils, we added a few extra wood chips to help the processes along.
Letting the mixture sit for around 28 days (with occasional stirring) is done to help us to control the temperature of the feedstock and ultimately the worm bin — note if the worm bin gets too warm it will kill your worms. As compost decays it heats up in processes known as a thermophilic compost cycle — hard science aside, the process lasts about 28 day during which time the feedstock will rise in temperature, some bad bugs and pathogens are killed off, and worm-hurting toxins are neutralized before finally the temperature returns to normal at the end of the cycle, at which point it can be fed to the worms. It’s kind of like quasi-pasteurizing your worm food.
Notably, this heating process is aerobic, which means the mixture needs fresh air to work. This can be achieved either through a fancy aeration system that blows compressed air directly through the feedstock or simply stirring the mixture every few days — we obviously went for the fancy aeration system but only because we deemed it more fun to engineer and build an aeration system than to manually stir compost.
Letting the mixture sit and “bake” for 28 days is a crucial step in making worm feedstock — honestly, it’s pretty much the only step…don’t skip it.
The last key element in creating a good worm feedstock is consistency. Consistency in the end product (i.e. worm castings) begins with consistency in the feedstock. That is to say, if one can consistently feed the worms the exact same food then the castings produced should be of a consistent quality and thus consistently bestow the same benefits upon the crop.
This consistency is crucial when creating your own worm castings as it allows for the product to be used with consistent results across the various crop types, year after year with predictable results. And it all begins with the feedstock.