One of the oldest references to eggplant is in the fifth century Chinese book. A black dye was made from the plant and used by ladies of fashion to stain their teeth, which, after polishing gleamed like metal.
Wild eggplant occurs in India and was first cultivated there. The Arabs took it to Spain, the Spaniards brought it to the Americas, and the Persians to Africa.
The eggplants received in various European countries in the sixteenth and seventeenth centuries varied greatly in shape and color. The very first known eggplants seem to have been of the class now know as ornamentals, the fruit white and resembling an egg. By 1806, both the purple and white ornamentals were growing in American gardens. Modern eggplants are oval, round, or elongated and have shiny purplish black fruit.
Eggplants are more susceptible to low-temperature injury, especially on cold nights than tomatoes. Don't set plants out until daily temperatures are in the 70 degree range. Plants that fail to grow because of cool weather become hardened and stunted; once stunted they seldom make the rapid growth necessary for quality fruit. If frost dates are unpredictable in your area and late frosts common, use hot caps or plastic covers.
Because eggplant can take 150 days to mature from seed, most gardeners grow transplants started indoors 6 to 9 weeks before the date of the average last frost. Transplant seedlings about 18 inches apart in rows 35 inches apart. The soil should be fertile and well-drained. Apply a side dressing of fertilizer in a month, and again in another month. Plants heavy with fruit may require some support Watch out for flea and potato beetles.
Harvest the fruit 75 to 95 days after setting out the transplants. For best eating quality. select fruit that has a high gloss and pick fruit when it is young, at about one third to two-thirds its normal size of 4 to 5 inches across. Early harvest encourages repeated flowering and fruit set. One test for maturity is to push on the side of the fruit and with the ball of the thumb, if the indentation does not spring back, the fruit is mature. If upon opening the fruit the seeds are brown, the best stage for eating has passed. Since the stem is woody, cut it with pruning shears, leaving some of the stem on the fruit.
Eggplant grows well in containers. Using a planting mix is good insurance against diseases that plaque eggplant in some areas. Varieties with medium to small fruits carried high on the plant are more attractive for container growing than are the low growing, heavy fruited types. Where summers are cool, place containers in the hot spots around the house, in the reflected heat from a south wall, for example.