Growing Eggplant in your Garden

Growing Eggplant in your Garden

The plots of standard, open-pollinated vegetables in my grandparents’ garden were year-to-year, as predictable as sunrise and sunset. Tradition has its place in gardening, but there comes a time when we must be adventurous and attempt something new.

(I well remember the daring sense of exoticism when my grandfather planted a hybrid dwarf watermelon, not from saved seed, but specially ordered from the Burpee catalog.) Each year I grow at least one untried plant, which is how I came to have eggplants in my garden. Among the edibles and ornamentals, the striking colors and shapes of new eggplant cultivars have much to offer in both the garden and the kitchen.

Deep purple, pink, lavender, and white eggplants (Solanum melongena) are relatively recent introductions to northern vegetable gardens, but their ancestors have been growing about the back hills of Africa, India, and China for centuries. And despite the mythology of their poisonous effects (see “A Shady Past”, right), eggplants, particularly their skins, contain substantial amounts of antioxidant phenolic compounds, cancer-fighting elements that gobble up free-radical scavengers in the bloodstream. Thus these once-feared fruits actually promote good health.

Of course, gardeners need to feed their souls as well as their bodies, and the voluptuous beauty of eggplants is reason enough to include them in planting plans. Their shapes range from small grape-sized fruits to classic large globes, in colors from the familiar deep purple through mauve, pink, lime, white and striped.

Despite their size, eggplants are classified as berry fruits; each one grows with a spiny cap called a calyx. All have both male and female characteristics and are self-pollinating. As well, they all have seeds that swell and darken as the fruits grow large and mature. To avoid seedy fruit, harvest them when they’re smaller and slightly immature.

A Shady Past

American president Thomas Jefferson (1743-1826), an innovative horticulturist, is credited with introducing the edible eggplant to North America, and it continues to be grown in his restored garden at Monticello, Virginia.

These striking yet misunderstood vegetables are cousins to tomatoes and potatoes (all members of the Solanaceae family), and are related to poisonous jimson weed (Datura stramonium) and belladonna (Atropa belladonna), a.k.a. deadly nightshade. Solanum is derived from the Latin word solemn, meaning “quieting,” referring to the soporific qualities of some nightshade plants.

Consequently, eggplant species were historically grown as ornamental garden plants, enjoyed for their vibrant violet flowers followed by deeply tinted fruits, but kept off the menu. Early eggplants were called mala insana, meaning “a mad apple,” in the belief they would cause.

Where Eggplants Thrive

Eggplants like as much sun and heat as they can get and benefit from wind protection. They are sensitive to cool temperatures and shouldn’t be outdoors when night temperatures fall below 12°C: cool temperatures will weaken and stunt plants, and they may not recover.

Growing them along a brick wall, which provides reflected warmth and protection from the cool air, is ideal. If the garden location is more exposed, consider providing a temporary stake-and-burlap wind barrier or baffle screen. Eggplants dislike heavy clay, preferring sandy loam amended with organic materials such as peat moss, compost, and composted manure.

Like their tomato cousins, eggplants are thirsty plants and heavy feeders, requiring consistent moisture and regular fertilizing. Surround each plant with a four-centimeter-thick mulch to help conserve moisture in its root zone.

Pull back the mulch and spread a handful of granular NPK 5-10-10 fertilizer around each plant every third week, but don’t dig it in, as the roots are shallow. Feed container-grown eggplants with a water-soluble 5-10-10 fertilizer every second week; plants may need staking to carry the weight of their berries.

Garden Growing tips

• Eggplants are sensitive to soil-borne fungal diseases such as verticillium, fusarium fungus (primarily a problem in warm climates), and tobacco mosaic virus. Select hybrid seed with inbred resistance to verticillium wilt, which infects the capillary system. Rotate eggplant locations in the garden each year, or grow in containers with the soilless mix to completely eliminate disease risk. (Tobacco smokers can spread the mosaic virus on their hands and should wear gloves when touching eggplants.)

• Start seeds eight weeks prior to planting out; they are slow to germinate. Plant several seeds in a 7.5-centimeter pot, one centimeter deep, and keep them warm by setting them near a heat register or on top of a refrigerator until germination occurs. Remove all but the strongest seedling.

• Young plants need warmth to grow. Try to maintain a temperature between 24 and 27°C, placing seedlings in a warm location with bright light. If seedlings under grow lights, hang a sheet of plastic film over the unit. A week before planting outside, move the plants to a cool windowsill and cut back their water by one-quarter.

• Transplant outdoors to a sunny and wind-protected location in mid-June, when the weather is consistently mild and warm.

• Harvest fruit when slightly immature, with smooth, glossy, firm flesh. Use pruners to cut fruit from the woody stems (wear gloves to avoid the sharp prickles on the berry calyx). Continually harvest fruit to encourage more flower production.