Eggplant are members of the same plant family as tomatoes and peppers (Solanaceae family) and cultural practices employed in eggplant production are similar to those crops. A native of the tropics, eggplant are warm-season plants that are more vulnerable to cold temperatures than tomatoes. A large selection of varieties makes eggplants available in several colors (for example, purplish black, red, white and variegated) and shapes (for example, egg-shaped, elongated and round). Most commercial varieties in the U.S. are purplish black in color and usually oval or teardrop in shape. Less commonly produced varieties include Asian eggplants, which tend to be long and slender, and baby, or miniature, eggplants.
U.S. per capita consumption of eggplant was approximately 0.9 pounds in 2012 (ERS 2013).Nutritionally, eggplant is low in fat, protein, and carbohydrates. It contains relatively low amounts of numerous vitamins and minerals, such as B1, B6, folate, copper, manganese, potassium and one cup of the skin and flesh provides approximately 10 percent of the daily value of fiber.
About 98 percent of the eggplant grown in the U.S. is produced for the fresh market, with the remainder used for processed products such as frozen entrees and specialty dips and appetizers (Outlook 2012).
Eggplant is a widely grown specialty vegetable in the United States. Although the USDA has not collected complete domestic production statistics for eggplant since 2001, the 2012 Census of Agriculture (2013) reports that eggplant was harvested on 3,400 farms in 2012, an increase of over 560 farms since 2007. However, acreage declined 17% in those five years. The leading states in eggplant production are New Jersey, California, and New York. An estimated 156.3 million pounds of eggplants were grown in the United States in 2012 (Yearbook ERS 2013). Production yields vary around the country with producers averaging approximately 20,000 pounds per acre.
Prices for eggplant vary depending on the type and season. A carton (approximately 25 pounds) averaged $23.50 in July 2015 (USDA AMS).
Based on most recent production and price averages, the estimated gross value per acre is approximately $18,800. The costs of production of eggplant vary depending the production location. It is labor-intensive, especially for harvest and post-harvest handling and packaging.
Eggplants are in the same family as capsicums and tomatoes and their growing requirements are similar. The eggplant plant thrives under warm to hot conditions and is extremely sensitive to frost. It is most suited to summer production in northern Victoria. Long periods of cool weather during the growing season will reduce yields by causing flowers to drop.
A range of cultivars are available including older open pollinated types as well as a range of hybrids. The fruit comes in many sizes and shapes although commercial varieties are purple-black in colour and usually oval or teardrop shaped. Some longer thin fruit are also marketed commercially.
A free-draining, deep, rich loam is preferred, but heavier soils with adequate drainage may also be used. The growing season takes around 110 days to maturity and the crop is harvested over an extended period until frost or cold stops growth. Conditions and cultural requirements are similar to those required for tomatoes, but eggplants require much higher temperatures. A sheltered sunny aspect is particularly important if the crop is to be grown in southern Victoria.
Because of the heat requirement, eggplant is usually planted in the field as seedlings. Plants can be direct-seeded but this must be delayed until soil temperatures reach a minimum of 21°C and is not practical. Weed control in direct-seeded crops is very difficult. Commercially, most seedlings are produced by commercial nurseries using cell trays.
In light soils a dressing of fowl or animal manures applied four weeks before planting is beneficial. Also add a base dressing of 500-600 kg per ha of NPK fertiliser such as 5:8:4 or 5:2:1.
If only artificial fertiliser is to be used increase the base dressing to 1000 kg per hectare.
Farmers should be aware of the potential dangers of using phosphatic fertilisers with high levels of cadmium.
Research has shown that the use of phosphatic fertilisers which contain the heavy metal cadmium as a contaminant can increase cadmium levels in both soil and potatoes. There are legal maximum levels of cadmium allowable for vegetables sold in Australia, however no violations have been recorded for eggplant as a result of survey investigations. Fertilisers containing cadmium in excess of 1mg/kg are required to state the following warning:
"WARNING -- this product contains cadmium. Continued use of this product in agricultural situations may lead to residue levels in plant and animal products in excess of the maximum level specified by the Australia New Zealand Food Standards Code and the accumulation of cadmium in soils."
It is in the grower's and consumer's interest to minimise the addition of cadmium to soils and agricultural produce. Growers should consult fertiliser suppliers or manufacturers for advice on the cadmium levels of fertilisers they are considering using. There are a number of low cadmium horticultural fertilisers marketed today. These have lower levels of cadmium than some superphosphate and other fertilisers.
Side-dressings can be applied throughout the growing season, using nitrogen at the rate of 180 kg per ha. Apply preferably when plants are 300 mm high and again when flowering commences.
Do not transplant seedlings until the ground temperature is from 18 to 20°C (usually mid-October to November depending upon the area). Plant in rows 600 - 1000 mm apart and space the plants 500 mm apart.
As eggplant grows slowly after transplanting do not over-water when the plants are small, but increase watering as they grow, particularly when flowering begins.
There are several pest of concern for eggplant growers, particularly aphids, thrips, leafhoppers, two-spotted mite, heliothis grubs and ceropid (spittle) bug.
These pests can be controlled with an appropriately registered chemical, The APVMA maintains a database of all chemicals registered for the control of pests in Australia. Refer to the APVMA or your chemical reseller for chemicals registered for the control of pests. Ensure you meet the relevant Maximum Residue Limits (MRLs) for the chemical in the end market, be it domestic or export.
Chemical users must ensure they read and understand all sections of the chemical label prior to use.
The removal of the lower leaves at the start of flowering will improve fruit set. Thin to 8-10 fruit per plant if required. Where regular harvesting is not maintained always remove any fruit that is over-mature.
Harvest eggplant when large enough and deep purple. Do not pick immature fruit, that is, fruit in which the seed has not hardened. Cut the tough stems with a sharp knife or secateurs.
Yields may vary from season to season and between paddocks, but growers can expect yields to range from 9-15 tonnes per hectare.
For information relating to the safe and appropriate use of chemicals, including management of chemical residues and licensing requirements, contact us and ask to speak to your local chemical standards officer or visit our Chemical use page