For Californians, Labor Day generally marks the end
In most areas planting should take place from July through August to allow for plenty of time for seeds and plants to grow and mature before the first autumn freeze.
Here is a list of the hardiest vegetables for cool-weather gardens:
- Arugula, from 21 to 40 days (baby or mature leaf size)
- Bush beans, about 60 days (have insulating fabric ready if early cold threatens)
- Beets and beet greens
- Braising greens mix (mustard, kale, collards, Asian greens…)
- Broccoli raab, about 40 days
- Broccoli (60 days from transplants started about 15 weeks before first frost; do try Piracicaba, whose florets are looser, delicious, and which easily produces lots of side shoots)
- Cabbage (60 days from transplants started about 15 weeks before first frost) or Napa cabbage (about 10 days faster)
- Carrots (a storage kind like Rolanka, plus some smaller types for fall eating)
- Cauliflower (60 days from transplants started about 14 weeks before frost; needs covering if frost threatens)
- Chard
- Chicory, endive, radicchio
- Cilantro
- Collards, about 60 days but nice as a baby green
- Cucumbers (bush type rated 60 days)
- Daikon (60 days) and other faster radishes
- Dill
- Kale, about 60 days but nice in half that time as a baby green
- Lettuce, leaf and head type and mesclun mix, about 30 days to first cutting
- Mustard greens, about 45 days (faster as baby greens to spice a salad)
- Peas, shelling, sugar snap, and snowpea type
- Radishes
- Scallions and other hardy bunching onions, for fall use and to overwinter for spring
- Spinach
- Squash, summer variety, bush type
- Turnips, 40-50 days, faster for greens, or rutabaga (90 days) if sown in earliest July or late June here; rutabaga
Frost is a key enemy of late summer vegetable plantings, so check for the date of the first expected frost and count backward the number of days to maturity to find the planting window for each crop. Harvest semi-hardy vegetables and root crops before a heavy freeze sets in. Alternately, a heavy mulch over root crops can extend harvest into winter or even spring if the winter is mild. Keep the ground warm as the temperature drops by draping blanket covers over staked wires. Individual plant covers, such as paper caps or milk jugs provide further frost protection for your fall crops.