Cover crops are any plant grown in the garden to improve a soil’s physical structure or its fertility or both. Cover crops are also often referred to as green manure. They can be grains, grasses, brassicas, or legumes. Usually, they’re grown during fall and winter and then turned under in the spring or left on the soil surface to act as a mulch. Gardeners can also use a quick-growing cover crop during the summer to fill the gap between crops.
In a previous article, we talked about the top three goals for using cover crops in the home garden.
Now, let's look at four more things we can accomplish in our gardens with cover crops:
Creating biomass.
Sometimes the whole goal is to just increase the soil organic matter. You’d think that those green manure crops would also create biomass and, while that’s true to some extent, there are some crops that just aren’t as bulky as others and don’t add as much to the soil. So, if you’re looking to just add mass, you’re going to choose specific crops.
The procedure on this is the same as green manure. Grow it, chop it down, and turn it under. If your goal is specifically biomass, turning it under in some way is going to accomplish this faster but if you’re more of a no-till or no-dig gardener and don’t want to turn the soil at all, then you should choose the cover crops that have the biggest root mass. Mustard, for example, is one of those that has a large amount of root mass that can be left in the soil and then if you just leave the crop on top of the soil it will eventually breakdown, too.
Breaking up soil/compaction control
If you have heavy clay soil that needs to be broken up or you have soil that is prone to being compacted, then there are cover crops specific to this goal. These are plants that either have very thick and interconnected root systems that break up the soil and prevent compaction or things that have large tap roots to loosen and aerate the soil.
In both of these instances, you’ll want to plant these crops to give them sufficient time to grow and produce their roots. If it’s something that will be mowed and removed, you’ll want to leave the roots in place. In some cases, the crop will winter kill and just be absorbed into the soil during the winter and there isn’t anything for the gardener to do but loosen the soil up and start planting in spring.
Attracting beneficial insects.
There is a lot to be said for any plant that will attract beneficials to our gardens and cover crops are no exception. This is especially true if you have a bed in the garden that won’t be used for an entire season because you need to break a disease cycle or build up soil nutrients or improve the texture. Planting a cover crop that will flower and draw in those insects can help your garden in all kinds of ways.
Choose the crop based on the length of time it will be in place but also for how easily it self-seeds. You do not want to use a crop like buckwheat as a cover crop to attract beneficials if need something in place long term. If the buckwheat goes to seed it can quickly become a nuisance weed in your garden. But if you use it in a bed that has a short break between crops in the summer, it will bloom very quickly and attract tons of pollinators in that short time, but then you’ll terminate it before it becomes a problem. If you have a space that will be cover cropped all season long, choose something like clover that will bloom but doesn’t become a nuisance after termination.
Forage
If you’re a homesteader and have livestock, or you have backyard chickens, or even pet rabbits you’re feeding, you can grow cover crops that also act as food for your animals.
Whether you put it in place and allow the animals to graze it down or chop it down and bring it to them, you can use cover crops to reduce your feed bill while also benefiting your garden at the same time.
With all the benefits to cover crops, it can be hard to decide which ones are best. The next article talks about which crops can be planted when, with a handy chart to help sort out the benefits of each!
Need more info? Check out Episode 118 of the podcast for more!
Your friend in the garden,
