Vegetables are designated "warm-season" or "cool-season," depending on the weather they need for best growth.
Warm-season vegetables, such as peppers and tomatoes, are summer crops; they require both warm soil and high temperatures to grow and produce fruit. They are killed by frost. Plant them after the last frost in spring.
Cool-season vegetables grow steadily at average temperatures 10° to 15°F/6° to 8°C below those needed by warm-season types. They can be planted in very early spring for early summer harvest or in late summer for harvest in fall and (in mild regions) winter. Many will endure short spells of frost ― but in hot weather, they become bitter tasting and often bolt to seed rather than producing edible parts. In areas with short growing seasons (fewer than 100 days) or cool, foggy summers, cool-season vegetables can be grown in summer.
A few vegetables are perennials: you plant them once, then harvest crops year after year. Give them their own garden area, so they won't be disturbed when you prepare soil for annual crops. Fertilize and mulch each spring; water as needed during the season.
Beans, Snap. Snap beans (also called string or green beans) have tender, fleshy pods. Besides the familiar green sort, you'll find types with yellow or purple pods. You can choose self-supporting (bush) or climbing (pole) varieties. Plant seeds of bush types 2 inches apart, in rows spaced 2 to 3 feet apart; thin seedlings to 4 inches apart. For pole beans, space seeds 4 to 6 inches apart and allow 3 feet between rows; support the plants on a trellis or plant them around a tepee. Thin seedlings to 6 inches apart. Begin harvest 50 to 70 days after sowing seeds.
Corn. Most kinds of corn do best in hot-summer areas, but early-maturing hybrid varieties will grow even in regions with cool summers. You must plant corn in a series of parallel rows so that wind can distribute the pollen effectively. Sow seeds directly in the garden, spacing them 4 to 6 inches apart in rows 2½ to 3 feet apart. Thin seedlings to 1 to 1½ feet apart. Harvest 60 to 100 days after sowing.
Cucumbers. Cucumber varieties include long green slicers, small kinds for pickling, and yellow, mild-flavored lemon cucumbers. In spring, sow groups of four to six seeds in hills 4 to 6 feet apart; thin seedlings to two or three per hill. Or sow two or three seeds in groups spaced 1½ feet apart at the base of a trellis; then thin seedlings to one per group. Harvest begins 50 to 100 days after sowing; be sure to harvest frequently to keep plants producing.
Melons. Cantaloupes (also known as muskmelons) are the easiest melons to grow, because they ripen the fastest. Planting through black plastic (see page 172) speeds harvest. In spring, sow four or five seeds per hill; space hills 4 to 6 feet apart. Thin seedlings to two per hill. Harvest 70 to 115 days after sowing.
Peppers. Sweet peppers are available in a range of colors, shapes, and sizes ― from bell types to long, slender frying peppers, in hues from green to bright yellow and purple. Hot peppers likewise offer a range of sizes, colors, and pungencies. Start seeds of sweet or hot peppers in flats indoors 6 to 8 weeks before planting time; or buy transplants. Set plants out in spring, spacing them 1½ to 2 feet apart in rows 2½ feet apart. Harvest 60 to 95 days after setting out plants.
Squash. There are two basic types of squash. Both are planted in spring, and both are available in vining or space-saving bush varieties. Summer squash (zucchini, crookneck, pattypan) are eaten when the fruit is small and tender; harvest 50 to 60 days after sowing. Winter squash form hard shells; they are harvested in fall (80 to 120 days after sowing) and can be stored for winter use. Sow seeds of bush types 1 foot apart in rows 3 to 5 feet apart; thin seedlings to 2 feet apart. Sow seeds of vining squash in hills spaced about 5 feet apart, placing four or five seeds in each hill; thin to two per hill.
Tomatoes. Easy to grow and prolific, tomatoes are a home-garden favorite. A huge number of varieties is available, varying from tiny cherry types to 2-pound giants; fruit colors include red, yellow, orange, and even pink. Start seeds in flats indoors 6 weeks before planting time; or buy transplants. Set out in the garden in spring, spacing plants 2 to 4 feet apart in rows 3 to 4 feet apart. Bury as much as half to three-quarters of the stem of each plant; roots will form along the buried part and strengthen the plant. Stake plants or place wire cylinders around them for support.
Beets. Besides basic red beets, nurseries and garden catalogs offer seeds of golden yellow and white varieties. The tender young leaves are edible. Sow in early spring (or in late summer, for a fall crop). Plant seeds 1 inch apart in rows spaced 1½ feet apart, or broadcast them in wide beds; thin seedlings to 2 to 3 inches apart. Harvest 45 to 65 days after sowing.
Broccoli. Easy-to-grow broccoli bears over a long season. Start seeds indoors 6 weeks before planting time; or buy transplants. In early spring (or in mid- to late summer, for a fall crop), set out plants 15 to 24 inches apart in rows spaced 2 to 3 feet apart. Or sow seeds directly in the garden, spacing them 4 inches apart; thin seedlings to 15 to 24 inches apart. Harvest 50 to 100 days after setting out plants, 90 to 140 days after sowing. Cut the heads before the buds begin to open. After the central head is harvested, side shoots will produce additional smaller heads.
Cabbage. In addition to the standard green cabbage, you can grow red and curly-leafed Savoy varieties. Start seeds indoors 6 weeks before planting time; or buy transplants. In early spring (or in mid- to late summer, for a fall crop), set plants 15 to 24 inches apart in rows spaced 2 to 4 feet apart. Or sow seeds directly in the garden, spacing them 4 inches apart; thin seedlings to 15 to 24 inches apart. Harvest 50 to 100 days after setting out plants, 90 to 140 days after sowing.
Carrots. If your garden soil is heavy, plant varieties with short roots. Plant seeds in early spring (or in late summer, for a fall crop). Sow ½ inch apart in rows spaced 1 to 2 feet apart; or broadcast seeds in wide beds. Thin seedlings to 2 to 4 inches apart. Harvest baby carrots 30 to 40 days after sowing, mature carrots 50 to 80 days after sowing.
Lettuce. Choose among leaf, butterhead, romaine (cos) and crisphead (also known as 'iceberg") lettuces. Start seeds in flats indoors about 4 weeks before planting time; or buy transplants. Set out transplants (or sow seed directly in the garden) in early spring; make successive plantings or sowings until daytime temperatures reach 75° to 80°F/24° to 27°C. Plant again in late summer and early autumn for fall crops.
Sow seeds of crisphead lettuce 2 inches apart in rows spaced 1½ to 2 feet apart; thin seedlings to 12 to 14 inches apart. Sow seeds of other lettuces 1 to 2 inches apart in rows spaced 1 to 2 feet apart; thin to 6 to 8 inches apart. Or broadcast seeds of all but crisphead lettuce in wide beds; thin to 6 inches apart. Harvest leaf lettuces 40 to 50 days after sowing, butterhead and romaine in 65 to 85 days, crisphead in 80 to 90 days.
Peas. Some kinds of peas are for shelling, some have edible pods ― and some can be harvested either way. Bush and vining types are available. In early spring (or in early fall, for a fall crop), sow seeds 1 inch apart in rows spaced 2 to 3 feet apart. Thin seedlings to 2 to 4 inches apart. Set up stakes or trellises for vining types at planting time. Harvest 55 to 70 days after sowing.
Spinach. Spinach bolts quickly into flower if the weather gets too warm or the days too long. For best results, sow seeds in early spring (or in early fall, for a fall crop). Space them 1 inch apart in rows 1 to 2½ feet apart; or broadcast over wide beds. Thin seedlings to 3 to 4 inches apart. Harvest 40 to 50 days after sowing.
Asparagus (Zones 1-24, 29-45). Because asparagus takes 3 years from seed to harvest, most people plant 1-year-old crowns, available from nurseries or mail-order catalogs in late winter. Space crowns 1½ feet apart in rows 3 to 6 feet apart.
Rhubarb (Zones 1-11, 14-24, 26-45; best in Zones 1-11, 34-45). Rhubarb sends up new leaves in spring and dies back in autumn. The reddish green leafstalks are the edible part; never eat the leaves, which are poisonous. Plant divisions in late winter or early spring, setting them 3 to 4 feet apart. Let plants grow for two full seasons before harvesting.