Building Garden Soil — Throw the Sink at It

Here’s a brief list of things we’re doing to boost the quality of our soil in our forest garden. I’m writing this because I saw a video a while back that explained why they don’t use worm castings, compost tea, leaf mulch, rock dust and so on any more. That video might confuse some people into thinking these things aren’t helpful. What actually happened is their soil has become so good (by using these materials!) in their small backyard garden raised beds that these soil amendments are no longer necessary. Since they’re only dealing with a few pickup loads of soil, it’s not overly difficult to create that much high quality soil.

In our case, and probably for most gardeners, we can’t get enough compost and good quality soil amendments. Our soil is far from perfect (compacted clay subsoil) and requires massive volumes of organic materials. So we’re “throwing the kitchen sink at it” as they say. In other words we’re using a wide range of materials to boost soil fertility. Each individual thing may only improve the garden a small percent, but it all adds up over time. Patience and persistence are key. Our soil is definitely improving every year using the following materials and methods:
– Fungal inoculated compost with indigenous microorganisms (IMO): we buy inoculated sugar cane compost by the dump truck load, but any good quality fungal inoculated compost should work. This step is very important. Our soil is now filling in with cotton candy like webs of fungi that will bring nutrients and water to plants.
– Sheet mulch: add layers of organic materials and let nature do the work of breaking them down over time. We’ve used primarily rice hulls, straw, manure and sugar cane compost.
– Worm tea: we make aerated worm tea with high quality worm castings, molasses, water, a plastic barrel and powerful aquarium pump.
– Worm tea foliar spray: same mix as above except sprayed on the leaves with a backpack style hand pressurized pump to boost growth and deter pests.
– Aged manure from small local farmers
– Compost from our local agricultural office (limited quantities only)
– Compost from worm trenches and vetiver grass that also slows erosion
– Ground covers like sunn hemp, nitrogen fixing plants like beans, peas and peanuts, and green manure from leucaena and vetiver trimmings.
– Thick straw mulch
– Effective Microorganisms (EM) made with fruit and vegetable kitchen scraps and free packets of EM starter from the local agricultural office. This is brewed into a sweet smelling mix that’s diluted and poured around the base of trees and on our compost piles.
– Keep roots in the ground (don’t let the soil sit fallow): This is actually one of the most important steps in my opinion. However, up till now this has been almost impossible in our case because we’ve been continuously raising the beds over the last 3 years with about 50 dump truck loads of soil amendments. Now our beds are raised to the proper height and we’re starting to fill in all the spaces between trees with a wider diversity of plants.
– Homemade compost: I’m working on a lengthy blog post about this. Stay tuned. I’ll explain how we turned about $400 worth of materials into $6,000 of compost.
– Small quantities of biochar (rice hull ash) and rock dust: a little goes a long way.
– Last but not least is proper watering. Now that our trees are established, I don’t water the trees so much as keep the soil moist to stimulate growth of beneficial microorganisms. (Critical when it doesn’t rain for 6 months.) This technique is confirmed by Jeff Lowenfels, author of Teaming With Microbes.