Feeding Healthy Soil

How to meet your soil's nutritional needs so it meets yours.

By Alison Grantham

Photography by Mitch Mandel


How to keep your soil healthyIn the organic system, soil is a living organism that provides nutritional support for people but also has nutritional needs of its own. For those who think of soil as nothing more than dirt, it may take an attitude adjustment to view soil as a living collection of creatures, along with minerals and bits of living material: iron oxides, unicellular bacteria, actinomycete filaments, flagellated protozoans, ciliated protozoans, amoebae, nematodes, root hairs, fine roots, elongate springtails, and mites. 

All of these substances have an essential role in organic soil health and the quantity and quality of an organic garden's glory. They break down the huge, unwieldy proteins and lignins in straw, leaves, and the wastes and remains of living creatures into simple, accessible compounds, like nitrate and ammonium, that plants transform back into spicy peppers and mellow watermelons. One organic tomato grower summed it up like this: "The soil is like a farmer's bank. You've got to keep making deposits into it all the time. If you withdraw from it until it's empty, you'll be out of business." 
When it comes to firing up a garden's resident soil microbes, the organic shed is filled with practical, adoptable soil-building tools, which for ease can be grouped by the benefits they provide. 
Soil Fertility and Regeneration
Key tools in organic soil fertility and regeneration include cover crops, crop rotation, compost, soil aeration, and mulch. Legume cover crops, such as winter peas or clovers, and edible legumes, such as beans, have the ability to transform nitrogen from the air into nitrogen in the soil. Legumes can provide the main serving of nitrogen for heavy-feeding crops like corn, melons, and tomatoes. After the crops are harvested, buckwheat or cereal rye cover crops can be sown to capture leftover nitrogen, saving it in a stable form to make it available for the next rotation. 
Microbes require certain working conditions to furnish the nutrients necessary for healthy harvests. Fresh air and a steady supply of food and water, plus protection from temperature extremes, will ensure productive soil. Covering the soil with biodegradable mulches, regularly incorporating fluffy composts, and minimizing compaction with good bed design are great ways to make sure the microbes stay munching and the plants producing. 
Keeping the beds planted with crops or cover crops or piled with mulch encourages roots and earthworms that will work to make the soil airy and loose. If the soil already suffers from compaction problems, try growing a cover crop with a big taproot, such as the tillage radish (also known as oilseed or daikon radish), to break up the hard subsurface soil layers. These crops are also great at bringing up minerals and micronutrients from the subsoil that shallow-rooted crops have a harder time reaching.