Mid- to late summer is prime time for gardeners a last chance to grow a second batch of fresh vegetables before plant-killing cold weather arrives. Add a few protective enclosures, such as cold frames, overhead sheets and hoops, and the harvest can be extended until Thanksgiving and beyond.
"The goal is to have fully grown, ready-to-pick plants that basically store themselves in the garden throughout the fall, so you can pick them as you need them over a long, sustained garden season," said Renee Shepherd, founder of Renee's Garden Seeds in Felton, near Santa Cruz.
You can plant many of the cool-weather crops from seed if you time it properly, she said. That means choosing fast-maturing varieties that can develop ahead of the average date for the first harsh cold or hard frost.
"Row covers for plant protection can always help extend the season when cold weather comes early, but if you plan and plant at the proper time, your fall harvests still will be abundant," Shepherd said.
Think ahead, though, because many neighborhood nurseries close or have picked-over inventories after the rush for spring supplies has ended.
"Some of the specialty garden centers and nurseries bring in extra plants for the fall, but you may have to purchase from another source and that takes some planning," said David Hillock, an extension consumer horticulturist with Oklahoma State University.
Before planting a second crop, turn the soil and refresh it. Fertilize to restore nutrients lost to the spring varieties.
And be sure to water. The ground is hot in late August, and new plants must get plenty of water, especially while getting started.
"Anything you can do to help conserve soil moisture should be done," said Rosie Lerner, a consumer horticulturist with Purdue University's Cooperative Extension. "Organic mulches cool the soil and decrease the need for moisture, a big plus when starting over in the summertime."
There may be some overlap between spring and fall gardens.
"Some beans and tomatoes might remain, perhaps things that will ripen in cooler weather," Hillock said. "But the typical fall garden crops tend to be more frost-tolerant."
Tender plants that usually stop growing or die after being nipped by frost include celery, eggplant, lima beans, cucumbers and summer squash.
Second-season crops capable of shrugging off fall cold spells or frosts especially if covered by inexpensive plastic "tents" and warmed with light bulbs include broccoli, cabbage, lettuce, kale, spinach and turnips.
"Here in Oklahoma, we have people harvesting tomatoes well into December if they have them covered," Hillock said.
And don't forget herbs. Thyme is the hardiest, along with sage, parsley and oregano.
There are other advantages to gardening in autumn: "Fewer pests and insects are around," Hillock said. "Temperatures are cooler with the fall rains. Disease isn't as frequent as it is with the springtime plants, but you do have to keep an eye out."