Planting a cover crop in the fall is an effective way to protect and improve your garden soil, through the off season. Cover crops perform several functions including increasing soil organic matter, fixing nitrogen, breaking up compacted soils, suppressing weeds, acting as a living mulch, promoting, and protecting soil microbial activity.
Cover crops are usually planted in the off-season, after harvest. Though often referred to as “green manure”, cover crops are the actual plants. They become green manure, once they are turned into the soil.
Commonly, cover crops fall into two categories: legumes and fast-growing grasses.
Both categories will add organic material to the soil, but legumes bring the added advantage of nitrogen fixing. The term nitrogen fixing refers to the plant’s ability to convert nitrogen from the air into a form useable by plants. When the cover crop worked into the soil, the nitrogen is released and becomes available for crops that are planted in the area. Clover, fava beans, hairy vetch are effective, nitrogen fixing cover crops.
Fast growing grasses are planted to add organic material as well as improve soil tilth and structure. This includes buckwheat, oats, and winter rye. These grasses develop deep root systems which helps aerate and reduce compaction, as well as protect soil microorganisms.
The time to plant a cover crop is as you finish harvesting and clear your crops. Cover crops can be planted in portions, which makes it easy to start putting down seed even as other parts of the garden are still producing.
There’s no need to till the soil. Rake up the soil with a bow rake, scatter the seed by hand, then cover lightly. Cover crop seeds will germinate quickly in the warm soils of late summer, early fall. The key is to keep the seed moist. Cover crops require little maintenance, once germinated. The main thing to watch for is to make sure the crop doesn’t go to seed.
In the spring, the crop needs to be turned into the ground. This can be accomplished by cutting down the crop with a mower or weed trimmer, or by digging it in with a garden fork or hoe.
Cover crops are well suited for all gardens, both in-ground and raised beds. They provide cover and stability for your soil through the winter months and help improve soil structure and fertility for the spring and summer garden.