While we are currently in the heat of summer, it’s not too early to start thinking about extending your vegetable garden’s growing season with some fall vegetables.
Rosie Lerner, retired Purdue Extension Horticulture Specialist, provides details about growing a successful fall garden (and you can even exhibit those vegetables at the DeKalb County Free Fall Fair).
Fall is an excellent time to grow many vegetable crops. During this season the gardener can take advantage of cooler temperatures and more plentiful moisture. Many spring-planted crops such as lettuce and spinach tend to bolt, or produce seed, and become bitter in response to the long, hot summer days. Fall gardening helps extend your gardening season so that you can continue to harvest produce after earlier crops have faded.
Vegetables such as broccoli, cauliflower, and Brussels sprouts are better adapted to fall gardening, since they produce best quality and flavor when they can mature during cooler weather. In Indiana, spring tends to heat up rather quickly. For many crops, insect and disease pests are not as much of a problem in fall plantings.
Many vegetable crops are well adapted to planting in late summer for a fall harvest. Use fast-maturing cultivars whenever possible to ensure a harvest before killing frost occurs. For DeKalb County, the average first killing frost falls between October 4 and October 10. You will want to count backwards from the frost date, using the number of days to maturity for the cultivars you want to grow to determine the last feasible planting date.
Planting
Remove all previous crop residues and any weed growth. Completely prepare the soil by rototilling or spading 6-8 inches deep. If spring crops were heavily fertilized, then no additional fertilization may be needed. However, 1-2 pounds of a general analysis fertilizer, such as 12-12-12, may be applied per 100 square feet of bed area. Be sure to thoroughly mix the fertilizer with the soil. Some gardeners prefer to side dress the plants with 1 pound of 10-10-10 per 25-30 feet of row placed 6-12 inches from the plants. Apply the side dressing 2-3 weeks after germination if plants appear to be growing slowly.
Late summer plantings often suffer from hot soil and a lack of water. Soils may form a hard crust over the seeds which can interfere with seed germination, particularly in heavy soils. Use a light mulch of vermiculite, compost, or potting soil over the seed row to prevent a crust from forming. Seeds of lettuce, peas, and spinach will not germinate well when the soil temperature is 85°F and above. Shading the soil and using a light mulch over the seed row will help keep the temperature more favorable for germination. Planting the seeds slightly deeper than spring plantings may also be beneficial, since temperatures will be slightly cooler.
Do not allow seedlings and young transplants to dry out excessively. Apply 1 inch of water in a single application each week to thoroughly moisten the soil. Young seedlings may need to be watered more often during the first week or two of growth. Young transplants may benefit from light shade for the first few days until their new roots become established.
Frost protection
Some vegetables that are already growing in the garden will continue to produce well into the fall, but are damaged by even a light frost. Some crops are considered semi-hardy and will withstand a light frost without protection. Others are hardy enough to withstand several hard frosts.
You can extend the fall growing season for tender crops by protecting them through early light frosts. Indiana often enjoys several more weeks of good growing weather after the first frost. Cover growing beds with blankets or throw-cloths supported by stakes or wire to prevent mechanical injury to the plants. Individual plants can be protected with such items as paper caps, milk jugs, plastic water-holding walls, and other commercially available products. The season can be extended even further by planting crops in a coldframe or hotbed.
ELYSIA RODGERS is ANR Educator for DeKalb County through the Purdue University Cooperative Extension Service.