Your soil is the most important part of your garden, but too many people forget to nurture their soil. Soil is a living thing, containing microbes, fungi, insect life and general 'creepy-crawlies' vital to plant health and vigor, as well as a receptacle for chemicals and trace elements. Doing a little soil prep every fall pays off each and every harvest.
First, add more organic matter. Use your rototiller or your spade, and dig under frostbitten plant material, grass clippings, leaves, wood chips, and compost. Avoid using any diseased plant material as compost – burn it first if there are no local restrictions on burning. If you live near any livestock, cover your garden with 1 – 2" of uncomposted manure, then disguise that with other organic materials, and let the whole thing winter over. A blanket of snow from December through March will turn all of it into about ¼" of the most beautiful topsoil you can imagine.
It’s also time to think about soil pH, or the acidity or alkalinity. The addition of organic materials can lower the pH, or make it more acidic. If your soil is already high in acid and you’d like to neutralize it, you can also add lime or wood ashes to your garden. Wood ashes are wickedly alkaline, but after a season or two, create an excellent haven for earthworms and add enough potash to the soil to grow wonderful root crops.
Finally, feed your fungi. Really. Many stores specializing in products for organic gardening and sustainable agriculture sell micorrhizal spores, which is a fungus that helps soil release its nutrients more easily. Micorrhiza needs to be fed in order to reproduce and survive the winter. Use a hose-end sprayer, and fill it halfway with gooey, blackstrap molasses. If you can find the sulphured kind, so much the better. Fill the rest of the sprayer with flat beer, and spray the solution over your garden beds. The sugar in the molasses feeds the existing fungi and beneficial bacteria in the soil, and the yeasts and enzymes in the beer add more.
You’ll literally make your soil come alive, and that will help your garden thrive next year.