For most northern-climate growers, the season is winding down.
However, what is done to the soil this fall will have a lot to do with how plants perform next spring and summer. I view fall as the most important time of year from a soil-improvement perspective.
In nature, trees shed their leaves and annual grasses die. Over the winter months, all this organic matter decomposes and replenishes the soil for next year's growth. It's recycling on a massive scale, and allows plants to thrive without humans adding fertilizer.
The home gardener or market grower can easily copy this procedure and it is well worth doing. After my crops were harvested and before the ground froze solid, I would scrape aside a couple inches of soil from about a 2-foot wide section beginning at one side of my garden. Then, I would run a mower over the leaves from large maple trees to grind them up, catching the pieces in the grass-clippings bag.
The ground-up leaves would be scattered in a thick layer where I had scraped the soil aside, and then covered with that soil. I never worried too much about covering every square inch of leaves or smoothing the soil.
Next, I scraped away another layer of soil and repeated the process until I had the entire garden blanketed with a layer of leaves with soil on top. This is also a good time to scatter broad-spectrum minerals.
That's it. By spring, nearly all the leaves had decomposed and I could use a small 4-prong rake to work up the soil before seeding. I find that I personally prefer lightly digging the top few inches of soil each season, but would never again disrupt the biological colonies and worm tunnels with deep roto-tilling.
This general method ("sheet composting") can be adapted to any plot of ground, using whatever organic materials are available. In desert areas, summers may be the time when soils are fallow. If you don't have a good supply of leaves or grass clippings or ???, then shredded newspapers are a favorite earthworm treat. (They use soy-based inks these days, so usually no toxic issues to worry about. However, I would not use slick colored pages.)
The key point is that the gradual decomposition over the winter prepares the leaves (or whatever you use) for maximum plant benefit. Blending in fresh organic matter just before planting can disrupt both the biology and chemistry of the soil. Give the process enough time - just as it happens in nature - and enjoy a terrific garden with nice loose soil next season.
Cheers, and good growing my friends,