As you harvest the last of your summer crops, realize that the steps you take now are the beginning of next year’s garden. You could just leave everything as it is, looking not so good through the winter. Mother Nature likes to keep things green, so will provide her own seeds to fill in the space if you don’t. That’s where the unwanted weeds come from. The spent plants from your summer crops are actually valuable compost material at the ready. Harvest them for your compost pile as you clean up your garden. Next year this time the compost you make now will be available to spread as fertilizer for your garden. If you have grown corn and sunflowers, those stalks are wonderful sources of carbon for your compost. Some folks till all their spent plants, including cornstalks, into the soil. However, since I advocate managing your garden with hand tools, I chop the stalks down and cut them into manageable lengths with a machete, as shown in the photo. The cornstalks then go into the compost pile with all the other harvestable plants, plus some soil. You can see me in action chopping cornstalks and adding them to the compost in my DVD Cover Crops and Compost Crops IN Your Garden. When you look at the plants in your garden, make sure to recognize their value as a compost material.
After you clean up the garden beds by harvesting compost material, you will need to plant cover crop seeds. If you have beds producing food through the winter, that’s great. It’s the rest of the garden I’m talking about. The crops you plant now will determine how each bed is to be used next year. If you intend to have bed space devoted to early season plantings, such as peas, lettuce, greens, and onions, you want the cover crops to be finished by then. Cereal rye, often called winter rye, is a great cover crop for winter. However, it is not so great if you are managing it with hand tools and you want to plant those early spring crops. The rye will have put down a tremendous amount of roots and be growing vigorously in early spring. Options to plant now in those beds destined for early spring crops are oats or Daikon radish, two crops that will winterkill if you get severe enough winter weather. Here in Virginia in Zone 7 we usually have weather that will cause these crops to winterkill, however I remember a few mild winters when they didn’t. I also remember a winter I planted oats in a bed that had compost piles on the bed just to the north of it. The compost provided enough protection to keep the oats growing into the spring.
If you choose the route of planting crops to winterkill, you need to get them planted early enough so that they have a chance to produce a large volume of biomass before the weather turns cold. If you don’t already have these crops in the ground, the time to plant them is NOW. Actually, anytime in the past three weeks would have been better. Another alternative for that space for early spring crops is to mulch it with leaves for the winter. The leaves will protect the soil over the winter and when you pull them back in early spring you will find a fine layer of compost where the leaves meet the soil. The worms would have been working on those leaves all winter. Pull the leaves back a couple weeks before you intend to plant to allow the sun to warm the soil.
You want a thick cover of plant growth with any cover crop. Planting at the right time will encourage that. The legumes, such as hairy vetch, crimson clover, and Austrian winter peas are often used as fall cover crops. It is best to get them in about a month before your last frost to ensure a good stand. That should encourage you to begin cleaning up the parts of your garden that have finished producing. Not all your garden beds will be host to the same cover crop, so you can do it bed by bed—an advantage over working on the whole garden at the same time. These legumes will begin to grow and will provide protection for the soil through the winter. In early spring they will take off, growing to their full capacity by the time of your last spring frost. You may have seen crimson clover flowering in garden beds at that time. You can cut this biomass with a sickle and add it to the compost pile. It would be a nitrogen component. You could lay it down as mulch right in the bed, but it would soon dissolve into the soil and not last as long as mulch that has more carbon. The advantage of the legumes is the nitrogen they leave in the soil from the nodules on their roots. If you should need the bed sooner than the date of your last frost, you could easily cut the legume a little early, leaving the roots. They are not so tenacious that you can’t plant into the bed soon after cutting.
The winter cover crop that will produce the most carbon for your compost and/or mulch is the rye that I mentioned earlier. It is also the crop that you can plant the latest into the fall and still have a good stand; making it a possible choice after things like tomatoes and peppers that produce until the first fall frost. You can let it grow to seed and cut it in early summer (mid-June here), giving you seed and mature straw. Or, you can cut it at pollen shed (about May 7 here) and leave it in the bed as mulch. Wait two weeks before planting to let the roots begin to die back. The bed would be suitable for putting in transplants, but not for seeds at that time. Often rye is planted with a legume. If you are planting late in the season, choose Austrian winter peas as a companion.
The information in my DVD Develop a Sustainable Vegetable Garden Plan and my book, Grow a Sustainable Diet, helps you to determine how to plan these cover/compost crops into your crop rotation. In the DVD you see me explaining a four bed rotation as I fill in the crop selections on a whiteboard. The book has three sample garden maps accompanied by explanations. The sample garden maps in the DVD and in the book have crops filling the beds for all twelve months of the year. Knowing how to fit enough cover crops in your garden plan to provide all of your compost and mulch material is definitely a skill that takes concentration and practice to learn. I hope the educational materials that I have produced will help many gardeners along that path. The most important thing is to just get started and plant something. Make note of your planting time and watch how it grows. The learning is in the doing.