Don’t wait! Fall, winter and overwinter vegetable crops need to get started now so they will have time to mature (for fall and winter harvest crops) or get well established enough to survive the winter.
Late July into August is an excellent time to plant many traditional fall and winter crops, such as broccoli, cabbage, kale, Swiss chard, and leeks, from transplants. A few crops, such as beets, turnips, onions, peas and carrots (for overwintering), and most greens can still be seeded. Of course, those who aren’t ready to give up on summer yet can still plant a couple more rounds of radishes from seed, or peas (for fall harvest) and lettuce from transplants.
Whatever you choose to plant, remember to refresh the soil with some good compost and fertilizer to get things growing. Also, late summer plantings are more likely to suffer from insect attacks than earlier plantings; consider using insect barrier fabric until they are big enough to resist and recover from pests.