In mild parts of Western Oregon and along most of the coast, it is possible to grow a succession of garden vegetables throughout most of the year. Gardeners can extend the season well into fall in many parts of the Pacific Northwest with a little knowledge and protection of their plants from the elements.
When space becomes available after harvesting the last spring-planted peas or greens, keep those veggies coming.
Even though your summer vegetables are growing like mad, late-July through mid-August is the time to plant many of your fall garden seeds in the Pacific Northwest. Transplants can be put into the ground up until the end of July for best odds of a fall and winter harvest. Lettuce and winter greens can be put in until September in many locations — but realize that each area has different growing requirements and results.
When planning a winter garden, choose the warmest, most sheltered spots in the garden, advises Ross Penhallegon, an Oregon State University Extension horticulturist. Choose heat-resistant and shade varieties and water them frequently as they grow until established, said Penhallegon.
Enation-resistant pea varieties include Oregon Pioneer shelling peas, Sugar Daddy snap peas and Oregon Sugar Pod II snow peas. Bolt-resistant greens include Tyee spinach and oak leaf lettuce. July and August is a good time to put in more carrots for fall and winter harvest, as well.
“Be sure you avoid poorly-drained or windy sites and places that are frost pockets,” said Penhallegon. “And add a good dose of organic matter to clay soils prior to planting for fall and winter.”
Keep carrot seeds moist until germination. In hot, dry weather, a damp burlap sack or light mulch over the row will increase germination. Keep it damp and check for germination every five days. Twenty to 30 feet of row should keep carrots coming into the spring. Royal Chantenay, Danvers Half Long and Merida are good carrots for planting in July and can be harvested all winter.
Other vegetable varieties that will grow through the winter include purple-sprouting broccoli, Utah-improved celery or President endive. Many kinds of Swiss chard, even if planted in the spring, will overwinter and re-sprout the following spring. Improved kales are a very reliable crop to plant in late July into early September.
Most members of the cabbage family can be harvested in fall or early winter if planted by early August. Many other greens in this group, such as Chinese cabbage, collards and mustard, hold well into the winter.
If you missed planting leeks in May, try garlic or overwintering Walla Walla sweet onions. Both can be planted in September, and harvested the following late spring into early summer.
Slugs can be a major problem in fall and winter vegetable gardens. Use properly labeled slug baits until cold weather arrives, said Penhallegon.
Many gardeners prefer the least toxic iron phosphate baits for environmental and safety reasons. Another way to reduce slugs is to thoroughly till the soil before planting. Tender crops such as buttercrunch or black-seeded Simpson lettuce especially need protection from both slugs and rain. For best results, grow them under cloches or cold frames during the late fall and winter.