I keep looking for ways to improve my garden soil without spending a lot of money. Cover crops do this quite well. The seed is cheap, and the crops don’t require much maintenance, though choosing them and timing their planting take some attention.
Cover crops protect the soil from being compacted by repeated freezing and thawing over the winter. I’ve planted frost-hardy annual ryegrass and oats as late as September--right around the first frost where I live--and had them grow a good soil-protecting mat before the ground froze hard.
During the growing season cover crops can outcompete weeds. I plant garlic in September on the beds that bore spring peas, but those pea vines die in July; I plant buckwheat in the interim so the bed doesn’t fill up with seeding dandelions and quackgrass.
Leguminous cover crops (clover, vetch, alfalfa, etc.) fix nitrogen in the soil. I plant crimson clover for winter cover on beds that are cleared of vegetables by August. Lately I’ve experimented with undersowing clover--giving the brussels sprouts and broccoli a long head start and then filling the spaces between them with clover. The clover feeds the established brassicas and outcompetes new weeds.
Deep-rooted subsoilers like alfalfa and sweet clover break up compacted soils and bring nutrients that are deep in the soil closer to the surface where vegetables can access them. The dead tops of cover crops can be left on beds as a mulch around seedlings, or raked off and added to the compost pile.
I always use cover crops that winter-kill. Perennial cover crops save a lot of upfront time, but they can also become persistent weeds in their own right. Even summer crops like buckwheat may need to be mown or clipped back before they go to seed.
This organic gardening site gives a good introduction to cover cropping.
Thanks for the info ... I never know what to do with the vegetable garden after the crops are harvested.