EGGPLANT (Solanum melongena)
By Master Gardener, Ellie Samuels
Eggplant (Solanum melongena) is a member of the nightshade (Solanaceae) family, along with tomatoes, tomatillos, peppers and potatoes. It is a beautiful vegetable that has been a staple in India and the Middle East for centuries. Its name is derived from the egg shape of its shiny fruit.
Eggplant are heat-loving, requiring germination in warm soil plus a long, warm to hot growing season. They differ mainly in the size, shape and color of the fruit. The skin is commonly purple but there are green, white, yellow and mottled varieties. Each plant usually produces three to four fruits. The only edible part of the plant is the fruit; the leaves are toxic.
To germinate eggplant indoors, start 8 to 9 weeks before the last expected frost date. Consider using a heating mat made for seeding—the optimal soil temperature for germination is 75 to 85 degrees. When the seedlings are about 3-inches tall and have three sets of leaves, they should be up-potted. When the seedlings are 6-inches tall, they are ready to be hardened off and planted. Whether purchasing transplants or growing them from seed, wait to plant them until the daytime temperatures are 70 degrees and nights remain above 55 degrees (ideally 65).
Eggplant likes to be planted in light, hummus-rich soil. The soil needs to be well drained and warm. You can use black plastic to warm the soil prior to planting and/or use row covers to mitigate dips in temperature. Eggplant needs regular water and full sun. Water deeply in basins around each plant. In addition to the immediate period after transplanting, regular water is important during flowering and fruit production. During drought periods, water can be reduced when fruit sets.
Use shade covers to protect plants when temperatures go above 95 degrees. Stake or support plants when fruit begins to develop. Feed eggplant with a fertilizer high in potassium and phosphorus and medium nitrogen or with compost tea or fish emulsion. Feed every 4 weeks by spreading the amendment in a circle around the base of each plant and scratch it in lightly. Do not overfeed as you will get lovely leaves but little fruit. Use mulch to keep weeds down and moisture in.
Common eggplant pests include the typical worms, beetles, mites and flies found in the summer food garden. Preventative controls include row covers, paper collars for cutworms and purchasing TMV—tomato mosaic virus—resistant varieties. Control pests by handpicking them, remembering to check the underside of leaves for egg masses that can be crushed. With serious beetle outbreaks, use Bt (Bacillus thuringiensis). Like tomatoes and other plants in this family, good cultural practices go a long way to preventing typical diseases. Avoid overhead watering, provide uniform irrigation to prevent blossom end rot, weed, purchase disease-resistant varieties, plant in nutrient-rich soil that is well-draining, provide good air circulation with adequate spacing, remove garden debris and rotate your Solanaceae crops at least every three years.
Harvest about 60-80 days after transplanting. Eggplants should be picked as soon as they are ripe. A glossy coating on the fruit is a sign of readiness. Mature fruit is soft enough that you can press it and leave an indentation. Use shears to cut the fruit from the plant. Store eggplant in the refrigerator.