{gardening} Cover Crops 101

As the community share cropping season gets going, we are planting and scheming and trying to improve the gardens compared to last year.  We already worked out our crop rotations during the winter, so now we are concentrating on weeding, feeding and cover cropping.  Cover crops are incredibly important for soil improvement, fertility and stabilization and for weed control.

We are bringing a new larger wheat patch into production this year but since we don’t have to plant the wheat until September, we will spend all summer getting the ground ready.  Before we start a new garden plot we try to go through at least half a season of cover cropping and weed control. For really weedy new gardens, it is good to sow buckwheat in the spring and till it in after six weeks, then let the soil sit for at least three weeks, cultivating it frequently to suppress the emerging weeds.  If we had a flame weeder we might work that in to our scorched earth policy toward weeds, but so far we have not experimented with that.  Too high tech for us, I suppose.

the tools we use for planting our cover crops from left to right, a broadcast seeder, an Earthway seed drill (instead of broadcasting), a lawn roller for pressing the seeds into the earth and a wheel cultivator

Preparing for wheat, and for most fall-planted crops, we do a cover crop season, using a three-legume mix, starting with crimson clover, field peas and fava beans (also called bell beans) in April and letting them grow for eight or more weeks.   All legumes fix nitrogen from the atmosphere (such a miracle) and all cover crops improve the organic matter in the soil, which affects soil tilth, that is, the quality of the soil.

white and black fava beans, crimson clover and lavender field peas

In late June or early July, we mow and till in the first cover crop, using our lawn mower and our rototiller.  Doing this suppresses the weeds that grew up into the cover crop before they go to seed.  We then sow a second planting of the same cover crop, except we swap cow peas for field peas since they tolerate hot weather better.  We let this second cover crop grow up for six weeks, then mow and till it in sometime in mid to late August.  We follow this second cover crop with two to four weeks of bare fallow, cultivating out all the weeds that peek up on a weekly basis.  Then in early September, we plant winter wheat which we will harvest the following July.  So our three year rotation is vegetables in year one, cover crop with a fall wheat and clover planting in year two, wheat harvest and clover in year three, vegetables again in year four.

cover crop in center before mowing

As noted above, we plant an intercrop with our wheat, that is, an understory plant that suppresses weeds during the growing season and stays in the ground to continue improving the soil after we harvest the crop.  In wheat we use Alyce white clover because it is low growing so it doesn’t shade the wheat and is shallowly rooted so it doesn’t compete with the wheat for water.  We used to use a medium red clover but it competed with our wheat and suppressed the yields.  White clover is a cold hardy legume, so it overwinters with the wheat and keeps growing through a second fall and spring after the wheat is harvested.  It is only about ten inches tall, which is tall enough to shade out young weeds without interfering with the crop.  Low white clover works well under any tall garden plants, like tomatoes or corn.

clover coming up beneath wheat

Our vegetable gardens follow our wheat, so the spring growth of understory clover gets mowed and tilled in two weeks before planting out the vegetables.  We could transplant into the clover, but we are always trying to get ahead of the weeds, so we till the clover in and keep cultivating. We plant in rows, far enough apart so we can easily cultivate between and within rows.  During the vegetable garden part of our crop rotation, we want to maintain clean cultivation to kill all the weeds before they go to seed so that we can deplete the weed seed bank.

After the first flush of early weeds have been killed, we spread mulch under plants that vine or sprawl a lot, like tomatoes, cukes and winter squash.  We do not mulch erect plants like corn, beans, eggplants, basil or peppers but keep weeding under them all season around once a week.  Potatoes are hilled, so they don’t need to be mulched if you rehill them a couple of times through the season, but you can mulch them if you have enough straw.  Don’t use hay for mulch! It contains beau coup weed seeds.  You can also try growing mulch in place, then cutting and spreading it, but we haven’t quite mastered that yet.  We’d like to figure out how to plant a companion plant that would grow into the fall as the vegetable garden winds down but haven’t gotten there yet.  We are thinking about drilling vetch into the rows in the summer, but the problem with vetch is that it doesn’t all germinate in the first year and can persist in places you don’t want it, like in your onions or wheat, where it can grow onto the young plants and drag them down with its tendrils.

buckwheat for weed suppression next to a row of broccoli plants

We also use cover crops following our main crops.  After we harvest garlic in mid July, for example, we plant a cover crop to improve the soil.  We generally use cowpeas, fava beans and crimson clover following garlic.  We mow and till it in the fall before it goes to seed and then immediately plant winter rye, which stays alive all winter.  We till the rye in around May 15.  It creates straw, holds nutrients so they don’t leach out of the soil during the spring run off, prevents erosion and, since it has allelopathic properties, chemically suppresses early weeds.  You shouldn’t direct seed into a garden plot following winter rye, but transplants do just fine.  It is great preparation for tomatoes, squash and other hot weather transplants, not so good for the seeds of lettuce, radishes or carrots.

So much to learn, so short a gardening season!  But then again, there is always next year.


Editor’s Note: Dianna’s gardening posts are so helpful, I wanted to include a ‘link love’ to her past posts:

In addition, Heather, Deanna, Erika & Jillian have written some stellar pieces on gardening too!


10 Comments Add yours

  1. Kelly says:

    Wow, this information is very helpful. I am just beginning to experiment with cover crops and I have had trouble finding good information about techniques that work. Thanks so much for the detailed explanations about each variety’s function and timing! Can you please tell me where you buy your cover crop seeds? I went searching locally for buckwheat this spring and could not find any. I am in Saratoga Springs. Thanks much!

    1. Dianna says:

      You are very welcome. We buy most of our seeds through Fedco Seeds, http://www.fedcoseeds.com/forms/ogs34_cat.pdf, a mail order co-op out of Maine, but also buy some locally or from other seed catalogs like Johnny’s. Fedco has a limited ordering period in spring, so they don’t necessarily sell all season long. Locally Agway has clovers and other seeds available, but they are not organic. Feel free to find us through Christina and talk if you need advice, my husband is a fanatic and would happy to be talk to you about what you are doing.

      1. Kelly says:

        Thanks for the info. I might just take you up on your offer to talk to your husband about cover crops. I have a lot of questions. I’ll get in touch with Christina. Thanks again!

  2. midnitechef says:

    Glad I found this post! Very informative. I just started a new veggie plot in spring, maybe I’ll try the rotations like you describe. Need to find a rotatiller…

    1. Dianna says:

      even if you don’t have a rototiller you can still plant cover crops. It is just how we do it.

  3. Peter says:

    Hi, love your site and cover crop methods. Have you tried sowing a winter cover crop (e.g. rye and vetch) around standing brassicas and let them go through the winter together? I figure they will do fine together, and when the brassicas are eventually harvested, the cover crop will still be there to do what we want of it.

    1. Dianna says:

      Thank you. We actually can’t overwinter brassica here because they die in the cold. We can keep kale through Thanksgiving or so, but nothing has every made it overwinter. Some of our cover crops make it through the winter, including rye and vetch, but we also overwinter some clovers and wheat. I don’t know where you are, but in a more moderate climate you can also use Austrian winter pea with brassica. Rye and wheat are most reliable in northern NY although sometimes there is some problem with allelopathy and rye, it tends to kill seeds you try to plant into it in spring. So where do you live?

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