Long and thin or round and fat, eggplants range from egg to melon sized. Their most interesting feature for gardeners, however, is the rainbow of different varieties: dark purple and pink to white -- even orange and green. Eggplants light up your garden with an iridescent glow, then they come indoors to star in hors d'oeuvres, main courses, grilled dishes, and pickled condiments. Eggplants (Solanum melongena) are attractive, tender herbaceous perennials normally grown as annuals. Their purple flowers and large, purple-tinged leaves combine with colorful fruit to make them a stunning addition for a vegetable or flower garden.
Eggplant truly is an international vegetable. Plant researchers theorize that eggplants were first eaten on the Indian subcontinent, and Chinese records note mild-flavored eggplant hundreds of years before the Christian era. By the fourth century, eggplants had found their way to the Arab world and from there traveled throughout the Mediterranean. Today, eggplant is a major crop in Asia and southern Europe. The variety selection reflects this international history. There are small, round green eggplants from Thailand, round orange eggplants from Turkey and lavender- and white-streaked eggplants from Italy.
The eggplant varieties most American gardeners are familiar with are the classic teardrop or oval-shaped, purple-skinned types. Although the size and heft of these modern varieties, such as 'Black Bell', are great for making eggplant parmesan, they only produce about 8 to 10 eggplants per plant, depending on where you live. For two to three times the yield (although the actual total weight is the same), try the long, thin, Asian types like 'Ping Tung Long'. The small, round varieties such as 'Bambino' are also appealing. These eggplants are great for the grill, in stir-fry dishes, or skewered.
The shapes, colors, and sizes of varieties are different, but when it comes to flavor, they all taste abouthe same, with perhaps one exception: White-skinned and mottled white varieties such as 'Asian Bride' and 'Purple Rain' have a milder flavor and less bitterness than the purple-skinned types. These varieties also have more tender skin that doesn't need peeling before cooking. However, if any eggplants are stressed by cool weather, disease or poor fertility, they'll produce thicker skinned and more bitter tasting fruits than they otherwise would.
Variety selection all comes down to personal preference. 'Rosa Bianca' is an outstanding heirloom. It's a vigorous plant with gray-green leaves and mild-flavored, slightly flattened violet globes. We also like 'Neon'. It's slim and oval, ripens to iridescent pink, and produces well.
Sow seeds, and keep them toasty. Sow seeds indoors 8 to 10 weeks before the last frost. Space them about 1/2 inch apart in a flat filled with a commercial seed-starting medium, and cover them with 1/4 inch of soil. Eggplant seeds germinate best in a warm environment (80oF) supplied by a heating mat. Keep the flats moist, and remember that the extra heat will cause them to dry out faster. For best germination, shut the mat off during the day to allow the soil temperature to drop 10oF. Eggplant seeds normally don't germinate all at once and can take 7 to 15 days to emerge.
Thin seedlings, and transplant them carefully. Once seedlings show their true leaves, thin to about 2 inches apart. If the plants start getting large enough that their leaves touch those of the adjacent plants, consider transplanting them into 5-inch pots. One week before transplanting into the garden, begin conditioning plants to the outdoors: Take them outside for a few hours the first day, and increase the amount of time each day until they stay out all day by the end of the week. Eggplants are very sensitive to transplant shock, so take extra care to harden them off properly.
Eggplants tropical plants that like extra heat. Don't rush to put them out in spring. Many gardeners wait until one to two weeks after they plant their main tomato and pepper crops to transplant eggplants into the garden. In cooler climates, lay black plastic over the beds two weeks before setting out your transplants to preheat the soil. If appropriate, plant near a stone, brick or rock wall that absorbs heat during the day and keeps the eggplants warm on chilly summer nights. Space plants 15 inches apart in rows and if temperatures are expected to be below 60oF, cover the plants with floating row covers to both keep them warm and protect them from insects.
Fertilize, water, and stake plants. Eggplants prefer deep, fertile garden soil, full sun, and warm temperatures. Before transplanting, work about 6 cubic feet (about a 3/4-inch layer) of compost into the top 6 inches of a 100-square-foot bed, which is enough space for 10 plants.
Once planted, eggplants need uniform moisture, warmth, and fertility to produce the best yields. Any stress on the plant will reduce yields and increase the chance of verticillium wilt, the most common disease of eggplants will attack. Water weekly if it doesn't rain. Feed every two weeks with fish emulsion at half the rate recommended for monthly use.
Alternatively, make one application of 15 to 20 pounds of composted manure, or 2 1/2 pounds of a low-nitrogen, complete fertilizer such as 5-20-20. As with other members of the Solanum family (potatoes and tomatoes), eggplants produce lush foliage but few fruits when fed large amounts of nitrogen.
Some varieties such as 'Bambino' and 'Easter Egg' only grow 1 to 2 feet tall, so they're easy to grow in containers. Choose a 12-inch-diameter container, fill it with potting soil, and place it in a sunny, warm spot outside. Keep the plant well watered and fertilized.
However, most varieties grow 3 to 4 feet tall. Stake these larger kinds to keep the fruit off the ground. To stake plants in a bed, drive 3-foot stakes into the ground after every third plant around the perimeter of the bed. When the plants are 10 to 12 inches tall, tie sisal twine (which can be composted later) to the first stake, and string it around each stake until all of the stakes are connected. Tie the twine around the bed once at 10 to 12 inches from the ground and, as the plants grow, again at 18 to 20 inches. The plants won't fall over, and the fruits will be straight.
It's best to grow eggplants in a part of the garden where you haven't grown any other Solanum crops -- tomatoes, potatoes, and peppers -- previously. Many pests of eggplants are pests of these related plants too. The chief scourge of young plants are flea beetles. These small, black beetles create a spray of holes in leaves when they feed. To keep flea beetles away, cover the transplants with floating row covers, and spray a botanical insecticide such as pyrethrum to control any beetles that sneak under the cover.
The Colorado potato beetle is a pest of mature plants, and often prefers eggplants to potatoes. Check under the leaves for the tell-tale masses of orange eggs and crush them. Spray Bt 'San Diego' on the larvae to control them.
The most common diseases are verticillium wilt and phomopsis blight. Verticillium is a soil-borne disease that attacks plants weakened by stress. The leaves begin to wilt and yellow, the yield is reduced, and sometimes the plants are lost. The best cures are rotating crops with unrelated crops, keeping plants stress-free, and growing early-maturing varieties. If none of these options work, grow plants in containers filled with a peat moss-based potting soil mix.
Phomopsis is a problem in hot, humid areas such as Florida and the Gulf Coast. The disease causes leaf spots, canker-like lesions on the stems and sunken dark areas on the fruits. Clean up plant debris well in fa and plant resistant varieties such as 'Florida Market' to control this disease.
One of the biggest mistakes home gardeners make with eggplant is that they harvest the fruits too late. The sooner you pick the fruits, the better they taste. Once the seeds begin to form and the skin has a dull appearance, the fruits are overripe. Begin to harvest eggplants when they are about one-third their maximum size. While the skin is still shiny, cut off the fruits with a sharp knife, leaving one inch of the green stem (the calyx). Store fruits in a 45° to 50° F room with high humidity to preserve their texture and flavor.
Here we've categorized eggplants by fruit shape so that you can compare otherwise similar varieties. Choose a short-season type if diseases are a problem in your garden, and choose an open-pollinated type ("OP") if you intend to save your own seeds for subsequent seasons. Large oval or teardrop fruits grow 3 to 4 feet tall and produce an average of 8 to 10 fruits that are best harvested when about 6 inches long. Cylindrical and long, thin shapes grow 2 to 3 feet tall and produce about 15 fruits per plant. Most fruits are 9 to 10 inches long and 1 to 2 inches wide. Small round shapes grow less than 2 feet tall so are well suited for growing in containers. Each plant produces an average of 20 to 25 fruits that are 1 to 3 inches long.
Variety - Days to harvest - Hybrid or OP - Skin color - Plant notes and fruit size
Large and Oval
Black Beauty - 75 - OP - Dark purple - Best in warmer areas of South and West. Imperial strain has larger fruits.
Black Bell - 60-65 - Hybrid - Dark purple - Good all-purpose, early, large-fruited variety.
Florida Market - 80- OP - Dark purple - Adapted to Deep South growing conditions; disease-resistant.
Ghostbuster - 80 - Hybrid - White turning yellow - Similar to but more productive than 'Casper'; harvest before skins turn yellow.
Purple Rain - 66 - Hybrid - Lavender with white streaks - Early and productive.
Rosa Bianca - 75 - OP - Lavender and white - Italian heirloom, very attractive fruits.
Violette di Firenze - 80 - OP - Violet - Unusual oval shape is ribbed like squash.
Asian Bride - 70 - Hybrid - White with lavender streaks - Six-inch-long fruits have very tender skins.
Farmer's Long - 70 - Hybrid - Violet-pink - Thin skinned and very prolific.
Ichiban - 61 - Hybrid - Dark purple - Purple-tinged leaves. Good in hot climates.
Little Fingers - 60-68 - OP - Purple - Vigorous producer.
Neon - 65 - Hybrid - Deep pink - 6- by 2-inch fruits.
Ping Tung Long - 65 - OP - Lavender - Good disease and heat resistance.
Tango - 60 - Hybrid - White - 7- by 2-inch fruits.
Thai long - 80 - OP - Light green - Compact, 1- to 2-foot-tall plant withstands light frost.
Vittoria - 61 - Hybrid - Purple - 9- by 2 1/2-inch fruits; prolific.
Small and Round
Bambino - 45 - Hybrid - Dark purple - Especially prolific.
Easter egg - 65 - OP - White turning to yellow and ornamental - Compact plant; egg-shaped fruits are both edible.
Kermit - 60 - Hybrid - Green with white streaks - Thai specialty fruit.
Turkish orange - 85 - OP - Green turning to orange - Bushy 2- to 3-foot plant with good insect resistance; harvest fruit while green before skin turns orange and bitter.
Article published on June 23, 2008.