Eggplant (Solanum melongena) is grown for its fruit, which is eaten when commercially ripe, either prepared or canned. Eggplants originated in India and Burma and were introduced into European cultivation in the 17th century.

The root system is well developed and represents 2% of the plant’s weight. Roots recover slowly after transplanting and require good soil preparation. The stem is erect, branched, and greenish-purple, and the leaves are large, ovoid-lanceolate, with long petioles, and darker veins. The flowers are large, solitary, purple-indigo. The fruit is a berry of various shapes and colors, with a smooth, shiny surface. The seeds are small, shiny, yellowish-grey.

Climate and soil requirements

Eggplants are very picky towards vegetation factors. The minimum germination temperature is 15℃, and plants grow normally at 27-32℃. During vegetation, at temperatures below 14℃, growth ceases, pollination does not take place, and flowers abort.

Eggplants need good exposure to sunlight, insufficient sunlight causes the flowers to abort and the plants and fruits remain small. Shading between plants can also cause flower abortion. Eggplants have high water requirements, and soil moisture should be maintained at 80% at a depth of 30-40 cm. Plants also have high nutrient requirements, preferring fertile, well-drained soils that warm up easily. Drafts can damage the eggplant crop, strong winds can damage the fruit, and it is recommended to form protective curtains around the eggplant plot with maize, sorghum, and sunflower plants.

Cultivation

EGGPLANTS CULTIVATION IN THE FIELD

Crop rotation

Eggplants can be grown after beans, peas, bulbs, cucurbits, and some root crops. Do not grow after eggplants, potatoes, onions, or garlic.

Soil preparation

This starts in autumn by applying basic fertilization. After fertilization, the soil must be mobilized to a depth of 30 cm, tilled, and leveled. In spring, apply fertilizers with a higher nitrogen content or balanced fertilizers.

Pre-emergent herbicides can be applied before planting. The soil can be shaped into raised beds to allow the soil to warm up more quickly.

Preparing and planting eggplant seedlings

The crop can be established only by seedlings produced in propagating greenhouses, polyhouses, or hotbeds. It is recommended to use special substrates, but also a mixture of soil, sand, and peat.

Sowing can be carried out between 25 February and 5 March, using certified or pre-treated seed. The seeds can be soaked in a stimulant solution.

The seeds should be sown in rows 5 cm apart and 1-2 cm between the seeds in rows, 1-2 cm deep. For one hectare of crop, about 1 kg of seed is needed. Immediately after sowing, the substrate must be treated with specific fungicides against damping-off. Once the plants have formed 2 true leaves, they should be planted in pots of 7 x 7 cm or 5 x 5 cm. After this work, you can apply a fertilizer to stimulate the root system development. One week after pricking out, foliar fertilization can be carried out, depending on the needs of the plants, to supply them with the nutrients needed for growth.

Eggplant seedlings should be 60 days old at planting.

Water the seedlings well the day before planting and harden 2-3 weeks before planting. This procedure involves opening the ventilation windows of the hotbed/polyhouse in the morning and closing them in the evening. In the last week, the windows should also be left open during the night so that the plants can acclimatize to the new environmental conditions.

Planting should be done when temperatures above 14℃ are reached in the soil at a depth of 15 cm. Calendaristically, the optimal time for planting is between 5 and 25 May. Watering can be done by drip irrigation before planting. The seedlings should be planted 10-15 cm deep, with 70-90 cm row spacing, and 30 cm spacing between plants per row. After planting, the plants must be watered and fertilized using root-stimulating fertilizers. The next time the plants are irrigated, you can apply a fertilizer to improve fertility and soil structure and to create better root absorption conditions.

Weed control

Eggplants prefer well-drained soil, is recommended to make 4-5 hoeings. When mulch is installed along the rows of plants, weeds in the rows can be removed by pruning or weeding. Mulching warms up the soil adjusts soil moisture, maintains a good phytosanitary condition, prevents weed growth, and reduces the number of maintenance works.

Pest and disease control

It is done by applying specific fungicide and insecticide treatments. To avoid the appearance of diseases or pests resistant to pesticides, it is recommended to alternate products. 

Other tips and care works

4 days after planting, fill the gaps with spare seedlings.

In general, the plants do not require trellising when cultivated in the field because the aerial part is quite developed and can support large fruits without problems. However, if planted in an area with strong winds, the plants may need support.

Suckers pruning is one of the works carried out in an eggplant crop and consists in eliminating the lateral shoots, which appear in the leaves’ axils. The suckers formed on the stem, until the first branching, must be completely removed.

To obtain early yields, you can carry out pinching, which consists of breaking the growing tips of the plant. The operation can be carried out after each shoot has formed 2-3 fruits.

Defoliation

It is a work that ensures crop aeration. Dried and diseased leaves should be removed from the culture. Once the first fruit has grown, the leaves can be removed until the first branching, to favor the air circulation.

Irrigation

Eggplants are high water consumers and watering is necessary even daily during periods of high temperatures. The best method of irrigation is drip irrigation. The amount and frequency of watering are determined by environmental factors.

Fertilization

Eggplants require the application of both root and foliar fertilizers to obtain rich crops.

One to two weeks after planting, apply more phosphorus-rich or balanced fertilizers to encourage rooting. Foliar fertilizers may be applied, depending on plant needs and environmental conditions.

During the flowering and fruit set period, you can apply fertilizers with calcium and boron for good fruit binding.

Fruit growth requires higher amounts of potassium and potassium-rich fertilizers can be applied for this purpose.

To help plants overcome periods of stress, they can be fertilized with specific foliar and root fertilizers. Root fertilizers can be applied to improve soil structure and root uptake.

Harvesting

It is done by hand, by cutting the fruit stalk with scissors or a knife. The operation is carried out when the fruit reaches consumption maturity, i.e. they are elastic when pressed and have the specific color of the cultivated variety. The flesh must be greenish-white, tender and the seeds small and white. Harvesting should be staggered, at intervals of 5-6 days. If the optimum harvest time is exceeded, the flesh may become bitter and the seeds ripen, making the fruit less pleasant to eat.

EGGPLANT CULTIVATION IN PROTECTED AREAS

Similar to field cultivation, starting in autumn, after the previous crop has been removed. As the incidence of diseases and pests is higher in protected areas, it is recommended to disinfect with specific products before planting the seedlings.

Planting

It is made with seedlings produced in heated polyhouses, according to the procedure described above.

Seedling preparation and planting work are similar to that of field cultivation, except for a few of them. Thus, sowing takes place between 1 and 10 February and planting between 5 and 10 April, when soil temperatures are a constant 15℃. When hardening the seedlings, considering that the outside temperatures can be quite low during that period, do not leave the ventilation windows open overnight.

As planting distances, you can use 90 cm between rows and 35-40 cm between plants, per row. To have easier access to the works, it is recommended to plant in strips of two rows at 60 cm between them and 120 cm between strips, with 35-40 cm between plants.

In protected areas, soil mulching can be done on the entire surface.

Eggplant crop in protected areas requires trellising. The trellising is usually made with string and the plants are guided by it. Remove all the suckers at the base of the plant and leave 2-4 more vigorous branches for training and fruiting.

The leaves at the base can be removed as they age.

Plants grown in protected areas have strong growth and require more frequent watering and more water than plants grown in the field. Fertilization can be applied by drip irrigation using water-soluble fertilizers. Root fertilization can be complemented by foliar fertilization.

The culture should be aired daily, in the hottest moments of the day.

Harvesting

It is carried out at consumption maturity, by cutting the fruit stalk.