Ted W. Gastier
The eggplant is probably a native of India and has been cultivated for a long time. It is a member of the nightshade family, making it a close relative of the tomato, pepper and potato. When compared to its relatives, the eggplant is of limited importance. Its use in appealing dishes make this vegetable highly desired by those familiar with it.
The eggplant is a very tender plant that requires a long, warm season for successful production. The plants are killed by light frost and are injured by long periods of chilly, frostless weather. Plants should not be set out until all danger of frost has passed.
Lime and fertilizer applications are best based on a soil test. Soil sample bags, forms and instructions are available from your county Extension office. In general, two pounds each of actual nitrogen, phosphorus (P2O5), and potash (K2O) per 1,000 square feet of garden space is adequate. An additional application of one pound of actual nitrogen per 1,000 sq. ft. after the fruit has set may be helpful to maintain plant development. Apply lime only if indicated by soil test results; pH should be maintained between 6.0 and 6.8.
The use of plastic mulch can increase the yield of eggplant by helping to warm the soil, by conserving moisture, and by controlling weeds. Plants may be planted in staggered double rows on each strip of plastic. Place the plastic on 5 foot centers and allow 18 inches between plants in each of the staggered rows. Because of the need for a long, warm growing season, it is best to use transplants. These may be purchased or started in peat pots or pellets 8 to 10 weeks before the anticipated planting time.
Extension Bulletin 736, Vegetables for Ohio Gardens recommends the following cultivated varieties, or "cultivars:"
Insect and mite pests of eggplant include flea beetles, Colorado potato beetle, aphids, and spider mites. Potato flea beetles eat small holes in leaves and can be particularly serious on small plants. Colorado potato beetle adults and larvae feed on eggplant leaves and can completely defoliate small plants if not controlled. Some Bacillus thuringiensis (B.t.) insecticides will control small larvae and are very safe to use. Hand removal of larger larvae and adults is also useful.
Four-year rotations with non-related crops and using plants grown from disease-free seeds will help control some eggplant diseases. A particularly damaging disease in eggplant is Verticillium wilt. It causes stunting in plants and interveinal yellowing, wilting, and dying of leaves. Avoid tomatoes, potatoes, peppers, okra, raspberries, or strawberries in rotation with eggplant. Contact your county Extension office for current control recommendations for insects, mites, and diseases.
The fruits of the eggplant are edible from the time they are one-third grown until ripe. They remain in an edible condition for several weeks after they become colored and fully grown. Skin should be shiny; seeds inside should not be brown or hard. Harvest will continue over an extended period if the fruit are removed when they are well-colored and of adequate size.
The fruits are usually cut from the plants since the stems are hard and woody. The large calyx (cap) and a short piece of stem are left on the fruit. Plants of most cultivars have sharp spines, so care is necessary when harvesting to prevent injury.
The author gratefully acknowledges James D. Utzinger, William M. Brooks, and E.C. Wittmeyer on whose original fact sheet this is based. This fact sheet was reviewed by Eugene Wittmeyer, professor emeritus, The Ohio State University, Department of Horticulture, and Marianne Riofrio, Extension Associate, The Ohio State University, Department of Horticulture.
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Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
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