Summer might be high season in the vegetable garden, but autumn brings wonderful rewards as well. Fast-growing salad crops will revive the most bedraggled fall gardens, and good care can keep sweet root crops and cabbage cousins growing for several weeks beyond the first frost. The tips below will help you extend your vegetable season long beyond the heat of summer.
The secret to having great fall garden vegetables is timing. That means thinking a little differently because you have to plan backward.
Start with your area's average first fall frost date. Then look at the number of days to harvest for planting fall vegetables. You should be able to find that number on the seed packet or in the catalog description. Use that number to count back from the first frost date. Then add two weeks, because many fall vegetables grow more slowly as days shorten in fall.
Here's an example: If your first fall frost typically occurs around October 31 and you want to grow 'French Breakfast' radishes, which mature in about 25 days, you'd plant them around September 22.
Make room for your fresh crop of fall vegetables by ripping out any varieties that are no longer performing well (such as tomatoes that have succumbed to disease or peas that have burned out from the heat) or you have already harvested (potatoes, onions, or sweet corn, for example). Pull any weeds so they don't steal moisture and nutrients from your new young plants.
If your fall garden vegetables have a lot of clay in the soil of the garden, it's helpful to work in some organic matter, such as compost, to get your fall vegetables off to a great start.
You'll probably grow most of the fall planting vegetables for your fall garden from seed. Use the extra seeds you didn't plant in the spring or purchase new ones. Happily, many garden centers put their seeds on discount late in the season, so you might be able to save a lot of money by planting fall vegetables. Want to save even more money? Save your seeds from last year's crop.
The basics of starting with seeds are the same in autumn as in spring—use a high-quality seed-starting mix for best results. If you reuse the containers you used for your seeds in spring, be sure to wash them in a solution of one part bleach to 10 parts water to kill any disease organisms that might be lurking about.
Test Garden Tip: If you live in a hot-summer climate, you might need to start seeds of your favorite cool-season vegetables indoors; many do better in air-conditioning than they do in the heat. If you start your seeds directly outdoors, plant them a little deeper than you would in spring; the soil is typically moister and cooler an extra inch or two down.
It's especially important to keep your vegetable plants well watered during the hot months of July, August, and even into September. The general rule is that most fall garden vegetables do best with about an inch of water a week in spring, summer, and fall. Once your seedlings or transplants are established, aim to give them one deep watering a week rather than several lighter waterings.
There may already be pests and diseases in your garden, so keep an eye out for holes or spots on plant leaves. Deal with insects and diseases promptly to minimize the damage.
Extend your growing season later into fall by protecting your plants from frost. A cloche is a classic, elegant way of protecting individual small plants. But for larger areas, cover the garden with an old sheet, blanket, tarp, or row cover.
Get a last blast from your veggie patch with quick crops that go from seed to table in 40 days or less. Sown in September, sprinters such as arugula, mustard, spinach, turnips, and crispy red radishes are ready to harvest in little more than a month. Also try pretty Asian greens, such as tatsoi or mizuna, which grow so fast that you will have baby plants to add to stir-fries and soups just three weeks after sowing.
Perhaps you will plant beets, carrots, green onions, Chinese cabbage, broccoli, and cabbages such as cauliflower and kohlrabi. Plant fall vegetables in late summer for fall harvest; in Zones 8-10, plant these crops as late as December. These fall vegetables can handle light frost, which actually makes them sweeter.
The hardiest fall vegetables—spinach and kale—often grow well into early winter. Thin crowded spinach to give the plants plenty of elbowroom, and stop picking leaves when freezing weather arrives. When protected by a blanket of snow or a plastic tunnel, spinach can survive winter and produce a flush of sweet leaves first thing in spring.
All of the fall garden vegetables below are suitable to plant in the fall. Some, such as beets and carrots, might need to be harvested when very small (but still tasty). When shopping for seeds, select the earliest-maturing varieties available.
The varieties of fall garden vegetables listed below will survive below-freezing temperatures if given some protection. During the first spell of cool weather, cover them with a blanket, cardboard box, or plastic tunnel. In Zones 8-9, where temperatures rarely dip below 20˚F, these fall vegetables will grow all winter. Dig beets, carrots, rutabagas, and turnips when the roots become plump and crisp; old plants left in the ground might develop unsightly cracks.