09/16/2026
The cheapest soil improvement available to a home gardener is a bag of seed and an empty bed.
A cover crop sown now grows through fall and holds the soil over winter instead of letting rain beat it into a crust, then gets turned in come spring as free organic matter.
Winter rye is the forgiving one. It takes the latest sowing date of anything you can buy and it survives whatever the winter does. The legumes, crimson clover and hairy vetch, host bacteria on their roots that pull nitrogen out of the air and leave it in the soil, but they want six to eight weeks before your first frost, and crimson clover is unreliable over winter much north of Pennsylvania. If you are reading this late, sow rye.
The one thing to get right in spring is the kill date. Turn a cover crop in two to three weeks before you plant, or it competes with what you actually wanted to grow.
Sow it in the next three weeks or wait until spring. Here is how to pick the crop:
https://spearheadspade.com/blogs/garden-guides/cover-crops-for-home-gardens