Ideally we like to have something growing on our gardens at all times. Bare soil is not something organic farmers like to see.
We use cover crops to keep the soil alive and nourished between our food crops. As we have three growing seasons here, we aim for each garden to have two cover crops for every one food crop. Those cover crops are tilled in and reincorporated into the soil, which helps build organic matter and improve soil tilth and fertility.
We plant our cover crops as soon as we can prepare the soil once we’ve finished harvesting the food crop. What we use as a cover crop depends on when we’re able to plant it. Here’s the schedule we’ve been using:
Early Spring: Spring oats
Before 8/20: buckwheat, millet, milo (or sorghum sudangrass)
After 8/20: oats, Austrian winter peas, crimson clover, vetch
After 9/14: winter peas, winter rye, crimson clover
After 10/15: winter rye, winter peas
After 11/5: winter rye
A convenient way to get fall covercrop mixes is to buy the deer or “wildlife” seed mixes that are sold at farm supply stores. Hunters use these to bait fields, but they’re a good mix of fall grasses (check the label to be sure) and save you the trouble of having to buy the seeds separately. These mixes don’t have enough crimson clover in them for me, so I usually buy some and add it to the mix.
This past year we added sunflowers as a cover crop behind our spring lettuce. They came up beautifully, smothered weeds well and produced a tremendous amount of biomass to put back in the soil. As a bonus we were able to sell a lot of the flowers and it’s easy to dry the heads and save seed for next year. The stalks are thick however and you’ll need to mow them down with a bushhog before trying to till them in. Even then they’re likely to wrap around the tiller so you’ll have to clear them off frequently.
We’ve got a couple of new cover crop ideas we’re going to try this year. We’re going to try growing tillage radishes after a couple of our summer crops (maybe cantaloupes and watermelons). These are large radishes that will winter-kill, then rot in the ground the following spring, incorporating nitrogen into the soil naturally. I was planning to try them last year but I didn’t want to buy a 50 lb bag of seed and our local supply store wouldn’t sell me less than that. This year I’ll either spring for an entire bag, find another source of the seed, or find some other farmer(s) who will go in with us on a bag. I’m anxious to see how they do. Getting nitrogen into the soil is especially important for us since we don’t use any synthetic fertilizers. With cover crops now we’ve been doing that with legumes, such as crimson clover. The radishes have the advantage of breaking compacted soil up too.
We’re also going to try using purple hull peas as a summer cover crop. We saved a lot more seed last year than we need, and these peas are great at fixing nitrogen. We grow a large garden of them every year but I’ve never used them as a cover crop before. They’re a hot weather crop and none of our current hot weather cover crops are legumes, so they seem an ideal candidate.
Of course peas are deer candy. For that matter it seems that most cover crops are. We barely have enough deer fencing to fence out our food crops so we’ll be at the mercy of the deer no matter what we plant. They’ve made it tough for us to grow our cover crops and much of the biomass that is intended for our soils ends up in deer bellies instead. But maybe the cover crop feasts we’ve provided have helped keep them out of our vegetable gardens.
I’m looking forward to gardens lush and green. On a very cold winter morning.