The cooler temperatures and moist soils of autumn allow gardeners another chance to grow cool-season vegetable crops that grew well last spring. In some cases, in regions with mild winters, fall is the time to plant some vegetable crops to overwinter and grow quickly first thing next spring. Start seeds of fall vegetables in early August and then transplant them into the garden bed in September. Take advantage of the fall weather up until hard freezes occur in late October to December.
Leaf Crop Vegetables
About 30 to 60 days before your expected fall date of hard freezes, when nighttime temps drop into the 27 to 30 degree F range, start sowing seeds of lettuce, spinach, collard greens, mustard and Swiss chard greens in two-week intervals. These fast-growing plants reach harvestable sizes quickly. To enjoy autumn cabbage heads that may be smaller in size than those grown in spring, put transplanted seedlings in the garden about 90 days before the expected date of hard freezes in late fall.
Root Crop Vegetables
These vegetable crops are protected by the soil when hard freezes occur, so you can let them in the ground after hard freezes kill the above-ground foliage. About 60 days before hard freezes occur in your garden in fall, sow seeds of leeks, kohlrabi, turnips, beets and carrots. About 30 to 45 days before hard freezes, plant radish seeds in weekly intervals. Also plant a row of chives that will grow into small, tender leaves for harvest. Garlic cloves are usually planted just after the first frost so that they can chill in the soil over the winter and then sprout up early next spring. In very cold winter regions, plant garlic cloves in spring so they are not frozen in the ground under the snow and ice.
Brussels sprouts, broccoli and cauliflower are perhaps the royalty of cool-season vegetable crops. Plant seeds of cauliflower and Brussels sprouts 90 days before the date you expect hard freezes in your garden. This often means sowing seeds in midsummer (late July or early August). If you have a frost-free fall in general, you can start cauliflower seeds around Labor Day and expect a harvest around Christmastime. Broccoli grows faster, so sow seeds of this vegetable 60 days before expected hard freezes. Consider sowing some broccoli seeds the same time as cauliflower so you have a succession of broccoli heads ready to harvest over several weeks later in autumn.