Salad greens, sweet root crops, and peas are cool-weather vegetables for fall and spring harvest. These edibles want to get their start in warm soil—either in the mid- or late-summer garden for autumn harvest or indoors or undercover for spring harvest; they eant to come out of the garden while temperatures are cool—averaging in the low 60°sF or cooler.
Sow cool-weather edibles for fall harvest by checking seed packets for “days to maturity” then add 14 days to the number on the packet and count back on the calendar from the average first frost date in your region; that is your seed starting date. For example, if the lettuce variety you are planting matures in 40 days, sow seed 54 days before the frost date.
For spring harvest, sow seed so that crops comes to harvest before daytime temperatures trend in the 60°sF; this may require starting seed indoors or under cover of a plastic tunnels or garden fabric row covers—to make sure the soil is warm enough for seed germination.
As well, you can protect fall harvest crops or extend the growing season by covering cool-weather edibles with row covers or plastic tunnels when temperatures dip. Plastic tunnels will keep crops 10°F warmer than the outside temperature; row covers will keep crops 4°F warmer or slightly more.
Most cool-weather crops will not be harmed by the first frost or two in autumn. Broccoli, kale, spinach, arugula, and turnips will produce deep into autumn and winter—even when temperatures dip below freezing at night. Root crops will actually become sweeter with frost.
Easy-to-Grow Crops for Cool Weather:
• Lettuce: Plants mature rapidly, so sow seeds every two weeks for a continuous harvest; easiest to sow in rows 12 to 18 inches apart and thin seedlings to 6 inches apart; water regularly; harvest leaf lettuce cut-and-come again; lettuce is sensitive to hot weather and will bolt to seed if temperatures are too warm—or plant in shaded area; lettuce grows best in soil rich in organic matter—using plenty of phosphorus, potassium, and nitrogen.
• Spinach: Plant in compost rich soil for best growth; optimal germination temperature is 50°F; requires cool weather and moisture retentive soil for flavorful harvest; for successive harvests, make small sowings weekly.
• Arugula: Add arugula to green salads for its nutty zing; thin to 6 inches apart and harvest leaves young and tender for best flavor—older leaves can be sharp and bitter.
• Mache: Cold hardy salad and cooking green with mild, nutty flavor also known as corn salad and lamb’s lettuce; from seed 90 days to harvest; plant in well-drained soil; thin seedlings to 6 inches apart; forms a 8-inch wide rosette which is harvested whole; quickly bolts in warm weather so harvest while temperatures are cool.
• Chard: Very easy to grow in hot weather and hardy to 20°F; plant in compost rich soil for flavorful growth; thin to 6 inches apart; requires a consistent supply of water; make successive sowings every four weeks then young plants can be harvested when about 12 inches tall—pull up root and all, or harvest cut-and-come again as needed.
• Broccoli raab: A favorite of Italian cooks this mustard-broccoli relative is also known as rapini and Chinese broccoli; unlike broccoli, broccoli raab forms loose sprouting shoots not heads; quick growing to 12 inches tall; harvest before the buds open for sweet flavor taste like broccoli but a tad stronger; steam for three minutes, drain then stir-fry in garlic and olive oil and serve with grated parmigiano.
• Kale: Matures in 60 to 80 days; plant in mid-summer for fall and winter crops or late winter for late winter and early spring crops in mild climates; harvest cut-and-come again; light frost sweetens flavor.
• Peas: Require 60 to 80 days from seed to maturity; sow varieties that mature at different times for a longer harvest or make successive sowings if winters are mild or summers are cool; sow in compost rich soil that is well drained; pick regularly, otherwise plants will stop producing.
• Radishes: Cool-weather crop that matures in just three weeks; prefers well-turned compost rich soil; thin plants to 1-inch spacing; good crop to interplant with slower growing vegetables; harvest as soon as they are edible size for best flavor.
• Carrots: Roots mature in 65 to 75 days from seed—pull as soon as root are edible for best flavor; soil must be free of stones and lumps for best root formation—raised beds are ideal; seeds germinate in 2 to 3 weeks—let soil be on the dry side until seedlings pop up, then keep growing bed evenly moist, mulching to conserve moisture if necessary; thin seedlings early to 2 inches apart.
• Beets: Mature in 55 to 80 days from seed; prefer loose, compost-rich soil that is moisture retentive for best root formation; add bone meal and rock potash before planting; thin seedlings to 3 inches apart when they are 6 inches tall—use thinnings for salads or cooking; when weather is warm mulch to conserve moisture and keep soil temperature evenly cool.
• Turnips and rutabaga: Turnips mature in about 60 days, rutabagas in about 90 days; sow in mid- or late-summer or very early spring; thin turnips to 2 to 3 inches apart, rutabagas from 3 to 4 inches apart; require steady moisture—mulch to keep soil evenly moist; cut turnips greens when roots are the size of a large egg; rutabagas will keep in the ground but turnips will become woody.
• Cilantro: Use leaves in salads or as a seasoning in cooked dishes; plant in composted, well-drained soil; regular water encourages growth and delays bolting; thin seedlings to 4 inches apart and later to 8 inches apart at maturity; harvest outer leaves as needed or chop them up and freeze them to use later; when plant goes to seed collect the gray-brown seeds (called coriander) and crush them to use in beans and stews.
• Leeks: Mature in 100 days; best to start in flats from seed then transplant seedlings to the garden; set about 4 inches apart when plants are 4 inches tall. Blanch shank of leek by mounding soil up around it or by covering it with a paper collar, or plant leeks in a trench 4 inches deep and fill in the trench as the plant grows; be sure to give leeks steady water.
• Calendulas: Daisy-like orange and yellow blooms can be added to salads for their tangy flavor; blooms from late fall through spring in mild-winter regions, from spring to mid-summer in cold-winter regions; plant in full sun in well-drained soil.
• Pansies and Violas: Use these brightly colored flowers in salads and garnishes for their mellow flavor and candied scent; winter and spring blooming in mild-winter regions, spring through summer in colder regions.