Cover crops are a confusing topic for most gardeners, and no wonder. Most books expect you to plow them under. To gardeners, that doesn't sound doable. But new research shows that soil-building comes easier than that: from roots.
Of course, the top growth is important; preventing weeds alone is a huge benefit. And preventing soil loss. But out of sight, the roots do much more. Like opening passages for oxygen, feeding earthworms--and dying.
When the tops are cut, the roots die and turn to compost right there in the soil. Compost that you don't have to haul, turn, or shovel. And we aren't talking small amounts here. Winter Rye makes 380 miles of roots per plant. The most fertile soils in the world are grasslands, where the roots grow and die in the soil year after year.
What to Plant? Let Nature be your guide.
Meadows and prairies have a mixture of grasses, legumes, flowers, and taprooted plants. The famously fertile topsoils of the Midwest were built by such plant communities. Use that soil-building synergy in your garden. Your mix should include:
Timing is important
The size of the root system depends on when you plant. It's best to sow cover crops 2-4 weeks before your first fall frost. * Don't be surprised if the plants don't get tall--they will be busy underground. In tests, crimson clover that was was only 2 inches tall by November nevertheless had roots 12 inches deep, with many nitrogen nodules already fertilizing the soil. Rye only 6 inches tall had roots 20 inches deep. All winter, the roots will be holding your soil, providing channels for water absorption, and adding tons of organic matter to your garden.
But how can you plant cover crops when the beds are still full of summer plants? Here are some options:
Don't forget pots and containers.
A low-growing, cover crop prevents your expensive soil mix from getting washed away or taken over by weeds. Calendula, poppies, salad greens, clover, and peas are great for this. If you aren't using the pot, cover it with its saucer to keep weeds out.
*You can find first and last frost dates online. Here is one place:
Tomatoes are coming in at my place and while I probably don't have to tell you how to enjoy tomatoes, I thought this was a good time to remind you of some simple ways I love.
Everyone has recipes for cooked or canned tomato sauce; I won't add to that stack. These are my favorite preparations for enjoying that fresh, fresh summer flavor and keeping it for winter.
Raw: hot-weather lunch
My favorite lunch, dinner, or snack this time of year. Grate, smash, or chop some garlic, add it to olive oil. 1-2 Tbsp oil per person is about right. Add a pinch of salt--this draws the flavor out of the garlic, (and incidentally protects you from botulism if you leave it at room temperature.) Slice a bunch of tomatoes, tear up some basil and some fresh mozzarella. Chop some Italian torpedo onions if you like them. Mix it all up and mop up with crusty bread. Ciabatta is good. Some people add balsamic vinegar.
Lightly Cooked: quick pasta dinner
Put 1/3 to 1/2 lb pasta on to boil. While the water is heating, chop up sweet red pepper--one big bell, or 5 of the small Italian type. A hot pepper if you like. Saute in a skillet with a couple of tablespoons of olive oil. When they are half-cooked (color has intensified but not soft yet) add 1/2 onion, chopped; a sprig of rosemary; a couple of sage leaves; and a few stems of thyme. If you have fennel, chop and add 1/2 cup of the bulb or a pinch of the leaves. Sprinkle on a pinch of salt as they cook. When the hard veggies are soft, chop or tear up 3-6 tomatoes, depending on size. (Last night I used 3 huge paste tomatoes torn in pieces.) When the juices are bubbling all across the pan, add a handfull of fresh mozzarella, torn up, or 1/4 cup grated parmesan. Put on the lid and take off the heat. (If you use very juicy tomatoes, cook it in an open pan until it thickens a bit. THEN add the cheese and turn off the heat.)
When your pasta is well-drained, put it in a bowl, dump on the sauce, and stir. Serves 2.
Roasted: add flavor, subtract skins
Roasting is a great way to give tomatoes an intense, smoky-fresh flavor to go with main dishes or over pasta. But is also a perfect way to get the skins off for canning or salsa. And honestly, which would you rather do--sit with a cold drink watching a barbeque fire or stand over a hot stove in August?
Getting the skins off by roasting is no more difficult than blanching them in water, and is actually faster, because I can fit so many more on the grill than in the pot. Best of all, this adds flavor instead of diluting it, and subtracts water instead of adding more to an already too-juicy product.
For easy, fast roasting, and wonderful flavor, roast the tomatoes or peppers on the barbeque grill. (I usually cook meat on the grill and then fill the grill with tomatoes, tomatillos, or peppers and put on the cover, because I like a very smoky flavor. For a less smoky flavor, leave it open. Either way, you need coals, not a roaring fire. Turn the peppers or tomatoes till the skin is blistered and loose on all sides. This is much more fun to do outdoors than standing over a stove, and faster, because the grill holds a lot.
You can use the broiler in their oven instead of a grill, or the traditional dry griddle on top of the stove. Same procedure—turn until all sides are blistered, loose, and browned. Use medium heat for chiles and low heat for tomatoes. It is OK if the tomatoes crack open. Remove them to a plate. As soon as they can be handled, take off the skins with a paper towel, under running water, or just peel off what comes easily with your fingers.
This is my preferred start when canning tomatoes for salsa or sauce. It gives the sauce a delicious smoky overtone that doesn’t need meat to seem extra rich and savory.
It is the easiest way to prepare them for freezing too. Roasting replaces the blanching step in freezing. Just cool and put into airtight containers. If you like, add a tablespoon of olive oil and a basil leaf. You can pull them out of the freezer all winter.
To us, the days are getting shorter, but to plants, the nights are getting longer. The cool and dark allow them to regenerate and to build new cells. Perennials start maturing their roots and sap for winter. Some are programed genetically to bloom or stop blooming in response to the longer dark. Even heat-lovers like tomatoes actually shut down at 90 degrees, so with more time to cool off, many plants have a sort of second spring. Some spring bloomers bloom again.
This is our cue to plant seeds for fall. The possibilities include all of the spring favorites like lettuce, peas, and broccoli. But fall is not just a lesser version of spring. There are good reasons to plan the fall garden as a season all its own, with delicacies and opportunities that spring doesn't have.
First, there are plants that are very hard to grow in spring but easy in the fall. Spinach, bulbing fennel, and Nappa cabbage are day-length-sensitive plants that bolt and get bitter in spring. In the shortening days of fall, they stay in vegetative growth, producing juicy, succulent vegetables for the table. Nappa cabbage is especially easy and quick. Its crunchy, juicy leaves are as mild as lettuce but hardier--good in salads, coleslaw, stir-fries, sandwiches, and preserved as kim-chee. Fennel is like a sweeter, more aromatic celery—and much easier to grow. Homegrown spinach is sweeter, and juicier than what's in the store. And instead of one quick spring harvest, you can cut leaves all winter.
Kale, cabbage, and broccoli sprout and grow best in fall. As young plants, they prefer warm weather, when their seeds would naturally fall to the ground and sprout. (They develop their great cold-hardiness as adult plants.) Transplanting is not a problem for this group—it actually stimulates root growth. Starting them in a shaded nursery bed is nice because it doesn't demand the care that pots do—and they'll wait for their garden space without getting pot-bound. If you need to use pots or flats, plan on giving them afternoon shade, and transplant to the garden or a larger pot within a month. Or sow them in large pots to start with.
Plant peas deeper than in spring, so they stay moist—about 1” deep. Soaking the seed for a couple of hours helps too. If you want to cut the tips for salad greens, it's best to plant a separate patch and harvest the top 4" of new growth. You can cut repeatedly once the plants are at least 16" tall.
Lettuce is probably the crop that will save you the most trips to the store if you grow it at home. So I like to plant it where I can reach it easily in the dark after work, or in the rain. Sow some every 2 weeks til frost. Its hardier, richer-tasting relatives--radicchio, chicory, and endive--are staples of the Italian winter kitchen. I love their slightly bittersweet flavor (like walnuts) in salad, pasta sauce or braised. They are a welcome change from the mustardy flavors that dominate winter greens. Winter lettuces and endives are bred to resist rain, mildew, and mold, as well as to be cold-hardy.
Lettuce is the opposite of kale. It wants to sprout in spring. So fool it. Put your packet of lettuce seeds in the fridge for a week. That artificial winter gets it ready to sprout. Sow in the evening, water well, and give it afternoon shade--an artificial spring that will gently introduce your lettuce to the realities of fall.
Jamie Chevalier lives and gardens on a river in the Coast Range. She has gardened professionally in Alaska and California, as well as living in a remote cabin and commercial fishing. She wrote the Bountiful Gardens catalog from 2009 to 2017, and now is proprietor of Quail Seeds.