(Editor's Note: This article was originally published on March 8, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
If you elect to grow your own eggplant (Solanum melongena var. esculentum), there are many lovely varieties to choose from. There are solid purples, purple-and-white streaked, white, green, dwarf, elongated, ribbed, smooth...take your pick. The disparity in appearance comes from the eggplant's diverse origins, with different types hailing from Africa, Italy, Thailand, India, China, the Ukraine and more.
The one thing eggplants don't like is cold weather, so it's a good idea to start seeds indoors. Even here in Texas, I don't set my eggplants out until at least mid-April because, although the danger of frost has long past, the soil has not adequately warmed until then. Gardeners in the mid- and northern regions will need to wait a bit longer.
Growing eggplants can be a test of patience. They are somewhat slow to get going, but a few early types will reward you with fruit before others. If you have a short summer, growing these early types is for you. Many of the Asian types are considered early - shop around when buying seeds and you'll be sure to find a type to fit your needs.
Treat them with lots of organic additives such as compost and earthworm castings. Mulch the soil once it's warmed up. In mid-summer, when air temperatures are consistently warm, you'll be surprised at the sudden burst of growth the plants will put on. Once the fruits start to get big, however, eggplants can flop over and break very easily, so install 3' high cages at planting time to keep the plants upright.
Flea beetles can be a common problem when growing eggplant, so keep your Neem oil spray handy. (Oil sprays should only be used in the morning or evening - not at midday. And try to hold off on spraying at all if ladybugs and honey bees are in the area.)
I've also found that, for some reason, fire ants love to take up residence around eggplants. For that, I use Spinosad in either the dry bait crystals or liquid drench form. (Spinosad has been deemed an organic substance by the USDA National Organic Standards Board.)
Eggplants should be harvested when firm and before their skin loses its glossy appearance. For this reason, many gardeners will harvest their eggplants very young. The fruits also tend to be less bitter at that stage. Cut each eggplant at the stem (watch out for thorns on the stem - some have them) with a sharp knife or gardening scissors. They will keep for about a week in the fridge.
The first thing you should know about eating eggplants is that they are members of the nightshade family. Experienced gardeners will know this generally translates to "possibly poisonous, except for the fruit". Do not use the leaves or flowers in cooking.
Second, eggplants are among the few foods containing sizable amounts of oxalates. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. Therefore, anyone with already existing and untreated kidney or gallbladder problems may want to avoid eating eggplant.
Lastly, folks with arthritis should limit their intake of all nightshade vegetables (which also includes tomatoes, peppers and green-skinned potatoes). Researchers think there may be a connection between joint stiffness and solanine, the toxin in nightshades that makes them somewhat poisonous.
The good news is that eggplants provide generous amounts of dietary fiber, potassium, manganese, copper and thiamin (vitamin B1). They are also a good source of vitamin B6, folate, magnesium and niacin. Eggplants also contain phytonutrients such as nasunin and chlorogenic acid, the latter of which is one of the most potent free radical scavengers found in plant tissues. Benefits attributed to chlorogenic acid include antimutagenic (anti-cancer), antimicrobial, anti-LDL (bad cholesterol) and antiviral activities.
Once picked, slice eggplants with a stainless steel knife. Peel large-fruited or white varieties - they can be bitterer than the other types. Also, before cooking, do what's called "sweating" your eggplant. After washing, remove the top (and peel, if you choose to do so), then cut the eggplant into whatever size your recipe calls for and place it in a colander in the sink. Salt the eggplant lightly and leave it alone for 30 minutes. Then rinse and use as directed. Not only will sweating cut down on bitterness, but this technique will also prevent the eggplant from soaking up excessive oil if you're frying it.
Eggplants are beautiful, relatively easy vegetables to grow and delicious, diversely nutritious vegetables to eat. Give them a try.