When to plant peppers, melons, and eggplants
Cool days and nights can be a problem for tender warm-season crops such peppers, melons, and eggplants. Temperatures in the 40s won’t kill these plants, but their growth will be stunted.
Wait to plant out these very tender crops until the lowest temperatures at night do not fall below 50°F to 55°F. (60° is even better!) If you plant sooner, use row covers, plastic tunnels, or cloches – or even baskets or cardboard boxes at night to protect these plants from cold during their formative early weeks of development.
Pre-warming the soil before planting with heat-absorbing black plastic is a good idea as well.
Take heart; if you wait to plant eggplants, peppers and melons when the temperatures are optimal, you will actually get an earlier and more abundant crop.
Planting time for peppers
Peppers grow best in air temperatures 65° to 80°F. Peppers are most easily grown from transplants. Start seed indoors seven to 10 weeks before the date you intend to set peppers into the garden. Peppers can be seeded in the garden or transplanted out two to three weeks after the last frost in spring, after the soil temperature has risen to at least 65°F. In temperatures greater than 85°F, peppers may drop their blossoms although set fruit will ripen. The ideal temperature for sweet peppers is a daytime temperature around 75°F and a nighttime temperature around 62°F.
Planting time for eggplants
Eggplant is sensitive to cold. It grows best where day temperatures are between 80° and 90°F and night temperatures between 70° and 80°F. Eggplant is best started indoors six to eight weeks before transplanting into the garden. Set transplants in the garden no sooner than two to three weeks after the average date of last frost in spring, or when daytime temperatures consistently reach 70°F. Eggplants planted too early will not develop. Eggplant requires up to 150 frost-free days to reach harvest.
Planting time for melons
Sow cantaloupe and watermelon seed in the garden or set out transplants three to four weeks after the last average frost date in spring. Start melon seed indoors about six weeks before transplanting seedlings into the garden; start seed in biodegradable peat or paper pots at least 4 inches in diameter that can be set wholly into the garden so as not to disturb roots. Melons grow best in air temperatures ranging from 70° to 90°F. If temperatures exceed 90°F for several days, flowers will drop without setting fruit. Muskmelons require 70 to 100 frost-free days to reach harvest and will tolerate no frost. In cool or short-season regions, grow smaller varieties that come to harvest quickest.
How to give peppers, eggplants and melons a good start
Grow peppers, melons, and eggplants in raised beds or on hills or mounds that warm early in the season. In late spring, about the time of the last expected frost, dig holes about 18 inches deep and wide. Throw a handful of bone meal or all-purpose vegetable fertilizer (or half a shovelful of aged steer manure) into the bottom of each hole then backfill with a mix of aged compost, sand, and native garden soil or a half-and-half mix of store-bought planting mix and native soil.
If you are not planting in a raised bed, top each hole with the same mix to form a mound about six inches high and a foot or two wide. Water in the soil and cover the bed or mound with black plastic sheeting (plastic mulch) or black landscape fabric that will absorb solar heat. Let the soil warm up for 10 days or more before sowing or transplanting.
Preparing plant holes and mounds with aged compost is important for the success of melon, eggplant, and pepper crops—more important than feeding plants later in the season. Compost and planting mix are rich in water holding humus. Consistent moisture is necessary for vine development and essential for fruit formation.
Steve Albert will give his annual workshop on tomato and pepper growing on March 25 at the Petaluma Library, and his annual workshop on tomato growing problems May 6 at the Healdsburg Library. Both workshops start at 10:30 a.m.
Steve Albert is the author of The Kitchen Garden Grower’s Guide available at Amazon.com. He teaches in the landscape design program at the U.C. Berkeley Extension. He lives in Oakmont.