Autumn is a great time to work on next year's garden. It's wonderful to be outside, and there are so many things we can do now which will provide generous benefits in fertility and ease of planting when spring arrives. What you're growing, and the state of your soil's health will determine your plan of action.
Even though the recent frost killed the sensitive basil, sweet potato, squash and cucumber 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 in the next several months.
Compost or other organic matter incorporated into the soil, mulch, or a cover crop, provides 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 will benefit from an annual application of compost. One half to one inch 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. If you don't make your own, it's good to know the source of your compost. Leaves, manure, wood and vegetable waste are desirable ingredients. Avoid compost made from sewage sludge, municipal waste or 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. Incorporating compost or manure helps to preserve its nutrients and makes the application more useful to soil organisms. For this job, we prefer shovels over rototillers because they are quiet and pollution-free.
If you are beginning or expanding a garden, now is the time to take up the sod. Few vegetables and flowers can compete with grass, even if it's been turned under. I've found that the best way to convert a grassy area into a garden is to get rid of the sod. With a sharp, straight-edged spade, it's possible to lift up the grass, root zone and all, in pieces about the size of a large book. After a year in the compost pile it will be decomposed enough to return to the garden to enhance fertility.
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 leach out into the ground water. Fertilizers made from the remains of living things and ground minerals depend on soil organisms to make their nutrients slowly available to the plants. Give those organisms the fall, winter and early spring to build a reserve of plant nutrition in humus.
Now is also the time to plant a winter cover crop which will add organic matter, stimulate soil organisms with its roots and insulate and protect 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.
There are many other autumn tasks, too: making compost with leaves and the unusable remains of this year's garden; preparing cold frames to grow winter vegetables; dividing perennials; processing the ongoing harvest and even some planting. We'll be putting in garlic later this month. Spinach, dill, coriander, poppies and some lettuces 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 the delicious rewards next season.
This is Bill Duesing, Living on the Earth
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