Tomato production in South Africa has become capital-intensive, with growers required to manage seed choice, soil preparation, irrigation, nutrition, climate, and pest control in a coordinated way. According to Werner Wessels, area sales manager at SADC South Countries, Syngenta Vegetable Seeds, "A holistic approach is needed. Balancing environmental conditions, plant physiology, water management, and soil health is important. When farmers understand this, they can make informed decisions and optimise their production for long-term success."
Jandri Venter, responsible for product development at Rijk Zwaan, notes that production costs have increased compared to 10 years ago. "Farmers who contemplate planting tomatoes should be prepared to pay more for inputs. In addition, retailers and consumers are demanding a higher quality product, and a more intensive crop protection programme is required." He adds that growers should secure market access before planting and adopt a three-market strategy covering supermarkets, the informal market, and fresh produce markets to spread risk.
Tomatoes move through six stages: germination, seedling phase, vegetative growth, flowering, fruit development, and harvesting. Each stage requires tailored irrigation, fertigation, and climate management. Germination depends on balanced moisture and temperature. Early root development is essential, as most root growth occurs before fruit set. During vegetative growth, water and nutrient demand rises and trellising and pruning are required, especially for indeterminate varieties.
Temperature management remains central. Tomatoes perform best at mean temperatures of 20°C to 24°C. Night temperatures between 15°C and 20°C support fruit set, while average daily temperatures above 32°C and night temperatures above 21°C reduce fruit set. Fruit set generally fails below 13°C.
Protected cultivation allows tighter control of temperature, humidity, irrigation, and pest management. High-tech systems integrate automated climate control, fertigation, and moisture management. Growth cycles under protection range from 140 to 150 days for short cycles to 10 to 11 months for long cycles, with nine months of harvesting. Light intensity directly affects sugar production, fruit development, and plant health.
In open-field systems, capital requirements are lower, but yields may vary due to weather exposure and pest pressure. Crop rotation, soil preparation, and ridging to depths of 200 mm to 400 mm support root health.
Water management requires precision. According to Jovan Erasmus, agronomist at Netafim Southern and East Africa, "Adequate moisture is necessary for good crop establishment, growth, fruit development as well as quality." He adds, "Efficiency in water application is of utmost importance." In soilless systems, short irrigation pulses and accurate nutrient dosing are required to control electrical conductivity, pH, and nutrient balance.
Disease pressure, including TSWV, TYLCV, Fusarium, and nematodes, requires resistant varieties and, in protected systems, resistant rootstocks. Balanced nutrition and careful monitoring help prevent vegetative imbalance and fruit quality disorders.
Source: Farmer's Weekly
