If you have an area of the garden that’s empty or the plants are on their way out then you should consider planting winter kill cover crops! Cover crops are any plant that you grow not to harvest but for some other benefit like weed suppression, mulch production, soil improvement, beneficial insect support, etc.
If you have an area of your garden that you want to plant early spring crops into next year winter kill cover crops will do wonders to improve the soil and prepare it for that spring planting and now, early to mid-September, is the time to plant them. Winter kill simply means those that will not survive the winter and thus will be killed by the winter. Planting a winter kill cover crop now is important so there is enough time to allow them to grow before the winter sets in. That way there is a lot of above ground growth that will die and act as a mulch to suppress weeds well into spring and provide food for worms and other beneficial soil organisms. If you wait too long to plant them they will just be short little plants and won’t actually provide much benefit to the soil before they die.
In St. Louis we have found the following cover crops to be good winter kill options: oats, berseem clover, phacelia, and tillage radish. These all reliably winter kill and each one of those 4 is good for a different thing. This is why we plant them together and sell seed packets of all 4 mixed together. However, if you have a specific need you can get just one or two and plant those together. Oats are great for producing a lot of biomass to create a thick mulch. Berseem clover will add nitrogen to your soil. Phacelia provides flowers that beneficial insects enjoy. Tillage radish produces a large taproot that helps to break up compaction.
All of these seeds can be broadcast seeded. So just weed the area you are going to plant, work up the surface a little, sprinkle the seed onto the surface, rake the soil a little to get the seed in good contact with the soil, and then water. Then watch it grow and wait till the coldest part of winter kills it. In the spring when it’s time to plant just pull the mulch back where you need to plant and you should have a nice friable soil ready to drop seeds into.
You can purchase Winter Kill Cover Crop packets from our online store. Each packet is enough seed for a 4’x10′ bed.