If you have been following along these past couple posts, you probably have some questions about choosing which cover crops to plant and where they should go. In order to know what to plant in a certain spot now, you need to know what is planned to go there after that. I hope you’ve made a map of your garden showing all your beds, drawing it to scale on graph paper first, then making copies to play with. Now is the best time to be planning your garden for 2012. If you know what your main season crop will be, you can better plan the preceding cover crop, which you will be planting soon.
Common choices for fall planting in my area in zone 7 are cereal rye (often referred to as winter rye), winter wheat, crimson clover, hairy vetch, Austrian winter peas, radish (oilseed, forage, or daikon), and oats. You can find information about all these crops and more by reading Managing Cover Crops Profitably, 3rd edition, published by SARE. I don’t sell this book from my website, but I do have copies for sale when I have a booth at events. I like having a book-in-hand, however this one is available FREE online at http://www.sare.org/ so you have no excuse for not using it. Check your seed catalogs for their selections of cover crop seeds and read the descriptions carefully to see if they will do well in your area. In the mid-Atlantic region we have Southern Exposure Seed Exchange to look to. Become acquainted with the seed companies in your region. Ask about cover crop choices locally, maybe from the farmers at the farmers markets, and check with the Cooperative Extension Service in your area. Their publications are online so you should be able to find appropriate information for your state. I know I have some readers out there from beyond the U.S. Welcome! I’m thrilled to have you along on this journey. It would be great if any of you, no matter where you are, would add a comment to this blog telling us where you live and what cover crops you find helpful.
Gather all the information about the cover crop choices for your area and put it in a section of the garden notebook that you would have made if you’ve been studying my garden plan video. That will be an easy reference to go back to. Now, for choosing which goes where.
Cereal rye is my favorite cover crop because of all the biomass it produces both above and below the ground, but it’s not appropriate for everywhere. If you want to get an early start next year with sugar snap peas, onion sets, and lettuce planted in early March, you are going to want that bed to be ready to plant then and not have a thick crop of rye growing there. If you are in an area where oats will winterkill, like I am, you could plant that in late August or early September. Another good choice is radish–oilseed, forage, or Daikon. You would want to plant that in late August or early September, also. These two crops need to grow a lot of biomass in the fall. They will succumb to the weather in January in my area. In the case of the radish, you want the plants to have the opportunity to grow large radishes that will poke good-sized holes in your clay. When it winterkills, the radishes compost in place and give back to the soil, leaving holes for air and water to come in. The leaves dissolve on top and the bed is soft and ready for your next crop. If you wait too long, Mother Nature will plant her own crop of weeds, so use these winterkilled crops where you are planting something early the next year. By the way, you can harvest the radishes for the table or fermenting crock until about New Years in my area in Zone 7. I mentioned clay soil, but cover crops are equally good for building up sandy soil. No matter what you have, clay or sand, adding organic matter is the solution to soil building.
My last frost date here is about April 25, so keep that in mind and adjust accordingly when figuring your times to plant. If you want to have the bed ready for your main season crop about April 1, three or four weeks before the last frost, that rye is still not going to be at a good place for you to work. Those beds are where you might want to have hairy vetch, Austrian winter peas or crimson clover growing. These crops can be taken as biomass for the compost pile at any point in April and into May. If they are flowering, you can likely cut the plant and leave the roots in place. If they aren’t flowering yet, pull them out, roots and all, for the compost. That will insure they won’t grow back. The soil will be nice and friable and ready for the next crop. These crops are legumes, plants that pull nitrogen from the air and accumulate it in the nodules on their roots. They make a short-lived mulch if you should try to just put it back on the bed, so better to add it to your compost. Better yet, make sure you are also adding some carbon to the compost at the same time, such as stalks or straw saved from other crops. Some people like to plant hairy vetch in a bed where they will have tomatoes go in the following year. I often plant Austrian winter peas that will be followed by potatoes.
Now, about that rye. Any plant is going to be at its most biomass when it’s flowering. After that point its energy begins to go toward making seeds. At my place the cereal rye is flowering (shedding pollen) around May 7. In the beds I am going to plant soon, I’ll cut the rye then, leaving it lie right there for two weeks to settle, then transplant into it. Keep in mind I said transplant. The roots are decomposing enough to transplant, but the bed is still too rough for sowing seeds, unlike the conditions left after the legumes or those winter killed crops I just told you about. Suggestions for crops transplanted into these pre-mulched beds are corn, tomatoes, peppers, and winter and summer squash.
If you want to grow the cereal rye or wheat out to seed, the harvest is not until mid-June. At that point the plant has fulfilled its duty producing seed and is on its way out. I cut the plants with a sickle near the ground and my harvest is seed (to eat or to plant) and straw for the compost pile. The roots decompose rapidly and you can make a furrow with a hoe right in the stubble and plant the next crop immediately. This is the time to plant the hot weather crops–those that enjoy soil temperatures of about 65 degrees, such as cowpeas. It is also a good time to put in a second or third planting of zucchini, cucumbers, or snap beans. Or maybe you’ve designated this bed for carrots and beets. I usually broadcast wheat and rye when I plant in the fall, but if I’m going to follow it with carrots and beets, I’ll plant it in rows close together. When the grain is cut, the stubble is in rows and I can easily make a furrow with a hoe between the rows and put in the seeds for the root crops. The stubble gives a little protective shade to get started.
Your timing and crop choices are likely to be different than mine, but this should give you some idea how it all works. As you work with your choices on your garden map, keep in mind rotations and put the arrows on your map showing the direction everything rotates. It all becomes sort of a juggling act. In order to get oats or radish in by early September, the previous crop needs to be finished by then. A bed where tomatoes or peppers are in there until frost is not a good choice. In my video, Develop a Sustainable Vegetable Garden Plan , I take you through a four bed plan, explaining the rotations and crop choices, including cover crops. The beds are full all twelve months. The companion CD, which has all the planning worksheets, also has a seven bed garden map that is based on the garden I show in the video. That map is for you to study to give you another example. Originally I wanted to use that one in the video, but it would have taken too much time to explain it, so we gave it to you on the CD. In my video, Cover Crops and Compost Crops IN Your Garden , you see my garden from March through November as I explain how to work with these crops.
The management techniques that I propose use only hand tools. The crops are carefully planned so that the harvest of one crop prepares the way for the next. People who use tillers do not have to plan quite so closely. They just churn everything up and go on to the next crop. That harms the soil structure, creates hardpan, and lets loose more nitrogen than the soil can handle at one time, losing nutrients. If you are late getting the cover crops in, cereal rye and Austrian winter peas are your best choices for a late planting. My first expected fall frost date here is in mid-October. I prefer to have everything in by the end of October, but I’ve planted these crops as late as mid-November, when necessary. It takes some practice learning which crops to plant and how to follow the growing rhythms . Once you learn the dance, you will see great changes happening in your soil.