Our potato plants died early last summer, so I had to dig the potatoes in late August. In addition to the potatoes, we always have empty garden space when we dig up the garlic and the pea vines have died.

For most of my gardening life, I just ignored those bare sections until the next spring. But last year Richard Brzozowski, the University of Maine Cooperative Extension’s food systems program administrator, in the Maine Home Garden News email on things to do in September, advised planting oats as a cover crop. (Sign up for the monthly newsletter at extension.umaine.edu.)

Cover crop of vetch, oats and clover. Cover crops suppress weeds and protect your soil. Jennifer Larsen Morrow/Shutterstock

I had never grown cover crops before, but I had been wanting to add more organic matter to the soil, and this seemed like a good way to do it.

We purchased 5 pounds of oat seed from Pinetree Garden Seeds in New Gloucester, but if I gardened in a more rural area, I would have followed Brzozowski’s suggestion and bought oats sold as horse feed at a farm store to save a bit of money.

He recommends oats because the crop will be killed off by the first hard frost and form a mat that will protect the soil during winter. The recommendation was to plant a half pound of oats per hundred square feet, but he suggested doubling or tripling the amount of seed if you’re planting later in the season because the oats won’t have as much time to grow before the frost kills them. He also suggested rolling the seeds with a large diameter piece of PVC pipe to get better germination, which I did.

In the spring, you can either till in the oats – which is what I did – or leave the mat in place, just clearing away a small space to put in the seed or seedlings for the coming year.

I didn’t quite get a mat, but the oats did grow fairly well. This year I will plant earlier – the garlic and peas are already out of the garden – and will probably plant the oats more thickly.

Adding organic matter to the soil is just one benefit of cover crops. They also inhibit weeds from sprouting, prevent the erosion of soil during hard fall rains, conserve moisture in the soil and help break up soil that you have compacted over the summer when you walked back and forth picking your crops.

Oats, of course, aren’t the only cover crop you can use in the vegetable garden. Other grains that are recommended include barley, annual ryegrass and winter rye. All three work much as the oats do.

Legumes, such as annual clovers, have the advantage of adding nitrogen to the soil, but they do a lot of their growing in the spring and are more difficult to till in. I wouldn’t recommend them for a home gardener.

Radishes are another crop recommended as a winter cover crop. A few years back I attended a lecture at the Maine Agricultural Show that recommended daikon radishes for the job of loosening up hard-packed soil. These radishes, planted in late summer, will penetrate eight inches or more into the garden. By the time planting season comes in the spring, the radishes will have rotted and the hole created by the roots will remain. (Good as daikon radishes taste, you are not going to eat these; they are instead working to help your soil.) This is especially beneficial for those who use no-till garden methods, the speaker at the Ag Show said.

For the home gardener, however, oats are probably the easiest choice, and that will be my choice as I harvest crops and clean up the spent plants as the gardening season continues.

For  plants like tomatoes and peppers, which I grow all season until they are killed by the first frost, I have another plan for adding organic matter. The leaves that I raked, shredded and stored in compost bins during the fall of 2018 will be perfect for spreading on the garden by then.

And the compost bins will be empty for this year’s leaves – although I dread thinking of that eventuality.

Tom Atwell is a freelance writer gardening in Cape Elizabeth. He can be contacted at: [email protected]

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