Autumn is a great time to work on next year's garden. It's wonderful to be outside, and there are many things we can do now which will provide generous benefits in fertility and ease of planting next spring. Exactly what you do will depend on what you're growing, and the state of your soil's health.
Even though the recent frost has killed the sensitive basil, sweet potato, squash, tomato and pepper plants, the soil is still alive and remains an actively functioning ecosystem (as complex as a rain forest) for long into the fall. Soil temperatures in the range of 50 to 70 or 80 degrees Fahrenheit are the most favorable for humus-accumulation. With colder temperatures soil-building processes slow down. Above 86 degrees, decomposition of humus exceeds its production. This neatly explains the nearly non-existent soils in the tropics (where all the carbon is in living things) and the deep peat bogs of the north which store carbon in that humus-rich material. Our Connecticut soil is about 60 degrees now, and with a covering of mulch or plants, will cool off slowly for the next several months.
If we turn under compost or other organic matter, mulch the soil, or grow a cover crop, we provide the raw materials which soil organisms use to create humus. Humus, of course, is the near-magic substance which is the most important component of healthy soil.
Almost every garden can use an annual application of good compost. One-half-to-one inch of compost can be applied every year. A five-gallon bucket of compost covers a three-foot-by-five-foot plot, one-half-inch deep. Seventy-five tons covers an acre, one inch deep. It's good to know the source of your compost. Composts made from leaves, manure, wood and vegetable waste are always good. Avoid compost made from sewage sludge, municipal waste or any toxic materials, of course. If you must use nearly fresh manure, it is better to turn it in now than to wait until the spring. Turning under compost or manure helps preserve its nutrients and makes the application more useful to soil organisms. For this job, we prefer shovels to rototillers because of their quiet, pollution-free operation.
If you are beginning or expanding a garden, this is a wonderful time to take up the sod for composting. Few of the vegetables and flowers we want to grow can compete with grass, even if it's been turned under. I've found that the best way to turn a grassy area into a garden is to get rid of the sod, or at least banish it to the compost pile for a year. Then, it can come back to enhance fertility.
The plentiful rain has softened up the soil, so with a sharp, straight-edged spade, it's possible to lift up the sod, root zone and all, in pieces about the size of a large book.
Whether you're just starting or have been gardening for awhile, this is a good time to take a soil test. The results tell you what you're working with and provide guidance in adding minerals, compost or other materials. Be sure to ask for organic recommendations. It doesn't make sense to add chemical fertilizers, particularly at this time of year because they just leach out into the ground water. Fertilizers made from the remains of living things and ground minerals release their nutrients slowly. They depend on soil organisms to make nutrients available to the plants. Give those organisms the fall, winter and early spring to build a reserve of nutrients in humus.
Now's the time to plant a winter cover crop. This adds organic matter, stimulates soil organisms with its roots and insulates and protects the soil. Around here, winter rye is most commonly used. Rye seed is inexpensive; it grows easily if planted by November, and is a beautiful, satisfying deep green color much of the winter.
Certainly, there're many other autumn tasks: Making compost with leaves and the unusable remains of this year's garden. Preparing the cold frames to grow winter vegetables, dividing perennials, the ongoing harvest and processing and even some planting. We'll be planting garlic this month. Spinach, dill, coriander, poppies and maybe lettuce can all be planted now for early crops next spring. However, the most important autumn work is building the fertility of your soil. You'll reap delicious rewards next year.
This is Bill Duesing, Living on the Earth
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