Eggplant

Introduction

Eggplant (family Solanaceae; Solanum melongena) is thought to have originated in Southern to Southeastern Asia. Eggplant is closely related to pepper, tomato, tobacco and potato, and shares diseases with some of these crops. Cultivation methods are similar to those for pepper, but it is more heat tolerant and cold sensitive.  Deep, well-drained sandy loam soils are ideal for eggplant. Southern slopes that warm early in the spring may yield better.

Types and Varieties

Eggplants come in a diverse array of shapes, colors and sizes, and preferences vary widely among markets. The most common type is large, oblong, and deep purple with a green calyx. Asian types are long and slender, often deep purple with purple calyxes. Specialty varieties include finger-sized eggplants, small round eggplants, and different colors in all shapes and sizes.

Eggplant Varieties
Oblong Large-Fruited Slender Long Asian
Beatrice Orient Express
Black Bell Millionaire
Black Beauty  
Classic Slender Finger
Dusky Diamond
Falcon Hansel 
Nadia Gretel (white)
Traviata Fairy Tale (striped)
Nubia (striped)  
White Lightning (white)  
Clara (white)  
Dancer (pink)  

 

Soil Fertility

Apply lime according to soil test results to maintain soil pH at 6.5 to 6.8.

Use a liquid starter fertilizer at transplanting, especially with cool soil conditions. Use a high phosphorus starter fertilizer mixed according to label directions (typically 3 lb/50 gal of water). Apply 8 fl oz (1 cup) per transplant. If plants are to be grown on plastic mulch, the amount of nitrogen fertilizer to be sidedressed can be reduced, since leaching is minimized. Nitrogen can be applied through drip/trickle or overhead irrigation. Drip fertigation is especially advantageous with plastic mulch. Too much nitrogen fertilization will lead to plants that are bushy, leafy and slow to bear fruit. See Plastic Mulch and Row Covers, and High Tunnels for more information.

Less nitrogen fertilizer will be needed if manure or legume sod was plowed down (see Table 1, Nitrogen Credits from Manure and Table 2, Nitrogen Credits from Previous Crops).

PLANT NUTRIENT RECOMMENDATION ACCORDING TO SOIL TEST RESULTS FOR EGGPLANT
EGGPLANT NITROGEN (N)* LB PER ACRE PHOSPHORUS (P) LB P2O5 PER ACRE POTASSIUM (K) LB K2O PER ACRE
SOIL TEST RESULTS   VERY LOW LOW OPTIMUM ABOVE OPTIMUM VERY LOW LOW OPTIMUM ABOVE OPTIMUM
Broadcast and Incorporate 50 150 100 25-50 0 150 100 50 0
Sidedress 3-4 Weeks after Planting 30-50 0 0 0 0 0 0 0 0
TOTAL RECOMMENDED 80-100 150 100 25-50 0 150 100 50 0
*SEE PLANT NUTRIENTS FOR INFORMATION ON NUTRIENT MANAGEMENT AND APPLICATION.

Planting

Eggplant is normally grown from transplants. Between 2 and 4 ounces of seed are required to produce plants for 1 acre. Germinate seeds in flats at 70 to 75°F. Move to 50-cell trays after emergence. Sowing directly into 50-cell trays will shorten the time needed to produce transplants by approximately 1 week. Good transplants are 6 to 8 weeks old, fairly large and slightly hardened. Transplant in the field with 18" (small plant types) to 30" (large plant types) between plants. This requires from 66 to 40 plants per 100' of row respectively. Allow 36 to 42" between rows. Eggplants are much less cold hardy than tomatoes. Plant eggplants out after overnight low temperatures are consistently above 50°F.

Field Culture

The use of black plastic mulch will usually result in increased early growth and yield with less damage from Verticillium wilt, perhaps because of a healthier, more vigorous plant at the time of infection. Eggplant benefits from irrigation during the period of flowering and fruit set. If soil moisture is limited at this time, yields will be reduced. Large plants may benefit from being staked. Use one 4.5' stake per plant. Temperatures above 90°F, and night temperatures below 60°F or above 70°F, can cause poor flowering and flowers drop. Fruit are also vulnerable to sunburn so enough leaf coverage is critical. 

Harvest and Storage

Fruit should be harvested by clipping them off with sharp shears when the outside color is a glossy purple, the fruit is firm and before the seed changes color. Soft fruit, loss of glossy color and dark colored seed are signs of over-maturity. Harvest fruit as they mature to ensure continued fruit set. Fruit can be stored up to 10 days at 50 to 55°F and 90% to 95% relative humidity.