The original eggplant is a species of nightshade and native to the Indian continent. It is commonly known in British English as aubergine but in South Africa mostly called brinjal. It is related to both the tomato and the potato and was originally domesticated in India and Bangladesh from the wild nightshade, the thorn or bitter apple.

Climate requirement

Climate is one of the most important factors when determining planting times. The wide variation in

climate in South Africa allows the planting and production of good quality eggplant in open fields in

various parts of the country all year. Eggplants are known to be a warm season crop. It can survive

certain amounts of cold units, but are intolerant of very low temperatures. An eggplant crop requires

very stable temperature ranges with minimums and maximums not being too wide apart.

Temperature variation might result in poor fruit quality or reduced yields. The minimum temperature is

around 10°C with the maximum being 34°C. Optimum temperatures are around 26 – 29°C.

Soil 

Brinjals (Eggplant) requires well drained loam to sandy loam soils, but will grow moderately well over a wide range of soil types. However certain criteria have to be satisfied in terms of the soil structure and content to make it commercially viable. 

These factors include: Nutrient composition, Compaction, Effective soil depth, pH, Crop rotation, Herbicide residues and of course, Water holding capacity.

Brinjal varieties

Different varieties of the plant produce fruit of different size, shape, and colour, though typically purple. The most widely cultivated varieties (cultivars) today are elongated ovoid, 12–25 cm long and 6–9 cm in a dark purple skin. Colours vary from white to yellow or green, as well as reddish-purple and dark purple.

Cultivation

Soil preparation improves the potential for profitable production of eggplant. Any primary soil

preparation must be aimed at creating growing conditions for plants to develop the optimal root

system in a specific soil profile. The highest percentage roots will be found in the top 600mm of the

soil. 

The advantages of soil preparation are that there are no restrictions on root development, little chance of compaction, more oxygen in the soil creating better root development. This will ensure higher yields and reduction in production costs as well as more vegetative growth. Further, proper soil preparation offers more tolerance to drought and stress, less root disease prevalence, horizontal and vertical compaction layers broken as well as better water retention. It also ensures increased uptake of moisture and nutrients.

The choice of preparation systems should be determined by the plant requirements and the soil type. Thereafter, economic factors should be considered. No standard system can be recommended on all soil types. The choice of preparation method should be made based on the clay content of the soil. For example on sandy soils the focus should be to reduce compaction and erosion, where on heavier soils it will be to reduce crust formation. 

Soil preparation should be done to depths varying between 200 – 400mm. Ridging is highly recommended, and should be done according to the land contours. The main advantage of ridging is to keep excess water away from the plant, improved oxygenation of the root zone, increased soil depth in the growing bed, to promote root development.

When to plant

The earliest period for seedling establishment would be when the soil and air temperatures at least meet the minimum requirements for plant growth. The latest seedling establishment period would be after allowance has been made for the growth and harvest periods to be completed before adverse conditions sets in. Due to the effect of certain factors being prevalent at specific locations, within each of these areas the planting times may be earlier or later than the times given below.

Establishment periods for the main production areas of South Africa will then be:

• Lowveld (frost free areas) – Feb to May
• Middleveld (moderate areas) – Sept to Dec
• Highveld (cold areas) – Oct to Nov
• Western Cape – Oct to Dec

Seedling establishment

Model 128 or 200 seedling trays are the most popular. Although more expensive, larger seedling trays lead to better and more root development. Seedlings take 4 – 6 weeks in summer to reach transplant maturity. Seedlings take about 8 weeks in winter to transplant maturity. Deep sowing is found to be more advantageous in warmer conditions.

Seed takes longer to surface due to cooler temperatures and longer growing distances. Shallow sowing is more advantageous in cooler conditions. Seed surface quicker due to warmer temperatures and short growing distances. Efficient levels of moisture are necessary. Seedlings should be grown in a well-aerated medium, which has good water holding capacity and at a pH of around 6.5. Generally, peat, bark and vermiculite mixes are used. 

Media problems typically include excessive tannins and low air filled porosity, which results in poor drainage and the build-up of green mould. The medium should be pre-enriched and the seedlings should be fertilized.

Seedling management is a critical factor, and the following points may result in physiological

disorders; through incorrect sowing times, cold temperatures, particularly below 7 °C, cold grown seedlings and over-fertilization of seedlings.

Planting

Brinjal (Eggplant) Plant population should be between 20-25 000 plant p/ha. The single most important factor when

making a decision around plant population is the type of chemical spraying system- or method that

the grower is going to use for the duration of the crop. Everything should be designed around this

implement so as to get in between rows to effectively control pests and diseases.

It is highly recommended to try and keep the between row spacing at 1.8 to 2.5 meters.If the distance between rows is 2 meters with the distance between plants 30 cm, one will have a plant population of

16 700 plants per ha.

Transplanting seedlings

The production of good quality, healthy seedlings require the correct choice of both variety and

a reputable seedling grower. The correct soil preparation, analyses and fertilizer application prior to planting also needs to be done. Before seedlings are collected from the nursery, land preparation should be completed and irrigation systems should be in place. At this point some growers already install the trellising system such as poles and first wires. 

Seedlings must be hardened off before leaving the nursery. This is done by making sure that excessive nitrogen and irrigation is kept to a minimum. Sometimes seedlings are received with flowers or buds already setting, it is recommended to remove them at planting in order to give the plant more energy to establish itself.

Irrigation

Under- or over irrigation can have a devastating effect on the outcome of a crop. It is therefore very

important to apply water at optimal times. Too little water might lead to sub-optimum yields, a decrease in the photosynthetic rate and developing stunted growth. It also causes no production of flowers, low percentage fruit set, slow fruit development, small fruit sizes and poor quality.

When scheduling irrigation, the size of the root system at the time of irrigation needs to be taken into

account. In general, the root system can be compared to the aerial growth of the plant. The roots

spread into the soil at a similar rate to which the aerial growth develops. Most roots occur in the top

500 – 600 mm of soil level, even at maturity. For this reason irrigation should be monitored at this

level with irrometers. Deep, thorough irrigations are preferable to light and regular watering intervals.

Drip or flood irrigation is preferable to overhead irrigation, due to susceptibility to foliar diseases. The

amounts of water used will vary depending on the climatic conditions. During the cooler months

eggplant require about 25mm per week and this might increase to 50mm under very hot, windy and

dry conditions. 

Harvesting and getting market-ready

Eggplant should be harvested once the fruit are fully matured, very firm and the desired colour

achieved. Most new generation varieties available on the markets today have what is called a

spineless calyx. The stem attachment has the advantage of not having any thorns present. This helps

with the ease of picking, packing and increases the pack out percentage as other fruit does not get

damaged.

Eggplant or Brinjals are popular with most communities and will add to a wholesome dish with other condiments. Happy eggplant producing! Contact your popular seedling grower or seedsman for more information for your area’s specific needs.

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