When to grow tomato and how?

Climate

• Tomatoes are frost-sensitive
•  At hot temperatures of 35oC and above result to poor pollination, 20 ° to 24 °C is optimum for growth, yield and fruit quality

Varieties

• Determinate:  Star 9003, Star 9006, Star 9009, Disco,
• Indeterminate: Trinity, Star 9037, Meryva, Newton, Ruby

Soil requirements

• Best results are obtained in deep, well-drained loams (ideal depth is 60cm)
• Soil analysis/testing
• Soil pH 5.5-6.5
• Consider the following; ­ nutrient composition, ­compaction, ­crop rotation, ­herbicide residues and water holding capacity.

Soil preparation

• Ridging is highly recommended, and should be done according to the land contours.
• The main advantage of ridging a tomato crop 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.

Planting times

• For good markets plant between September and October to harvest in February to March

Area                               Ideal time                                 Possible time

Highveld                        Jan,Sept-Oct                             Feb,March,Aug,Nov,Dec

Middleveld                     Feb-March, Aug,Sept-Oct        Jan,Apr,Jul,Nov,Dec

Lowveld                         April-May,Aug-Sept                March,Jan-Jul,Oct

Planting

• It is highly recommended to try and keep the between row spacing at 1.8 to 2.5 meters.
• Tomatoes grown on the ground for informal and fresh markets should have enough inter row spacing (minimum 1.8m)
• 60 cm between plants
• 12000-16000 plants per hectare
• Dissolve 50g (5 spoons) LAN plus insecticide for aphids in 10L water and water about 2000 seedlings before planting plus 7.5ml Actara

Transplanting

• Seedlings must be hardened off before transplanting
• Seedlings are ready at 4-5 weeks when they reach 12-14cm height
• At this point some growers already install the trellising system such as poles and first wires to lessen root damage

 Irrigation

• Farrow irrigation is commonly used but it spread soil-borne diseases while overheard irrigation spreads foliar diseases
• Drip irrigation is the best as it serves water and increase yields while reducing labour costs
• Insufficient water will increase the incidence of blossom end rot and the damage will be worse if the calcium content of the soil is too low.
• Water requirement is 500mm throughout the growing season (21mm/ week during first 4 weeks, 30mm/week for the following 8 weeks and 31mm/ week for the remaining period).
• When drip irrigation is used, irrigate for 2-3 hours every second day, although on exceptionally hot days irrigate every day for 2 hours.

Fertilization

• Fertilizer requirements should be based on soil test results
• Apply 2:3:4 at about 600kg/ha 1-2 weeks before planting.
• Recently transplanted plants should be medium green with fairly vigorous new growth
• Topdressing  with (LAN 100kg/ha + 50kg KCl) is required in the first six to eight weeks of growth at two to three week intervals thereafter

Trellising

• It is wise to apply trellising before planting to prevent root rot nematode exposure
• For open field trellising poles should be between 1.7 - 2.0 meters long, pitched 3-5m apart
• Lead staked tomatoes up between two wires or twine spaced at intervals of 30cm up the poles.
• Treated poles last longer, but caution should be taken with Creosote treated poles as this might burn some of the plants on hot days.
• Wire last longer and don’t have the ability to gather diseases.
• Rope could be infected with bacterial spores if reused
• The plant will make side shoots that grow to the sides of the main plant.
• These shoots should be neatly tucked in between the wires and not damaged.
• Constant trellising should be done.

Pruning

• To maximize photosynthetic efficiency and minimize risk of disease, indeterminate tomato types may be pruned. 
• It is recommended to remove side shoots before they are 5 cm in length.
• Scissors or finger tips can be used to remove the side shoot. 
• A disinfectant should be used to prevent the spread of disease.
• Don’t allow many stems to develop, fruit production may be slowed. 
• The indeterminate tomatoes can have one to many stems (commonly not more than four). 

Pests and diseases control

• A weekly spray programme for diseases and pests such as bollworm, looper, leaf miner, red spider mite and white fly is required.
• Warning on new economic pest Tuta absoluta which can lead to 100% loss of yield (Ampligo insecticide is recommended)
• Common diseases include late blight which can be prevented by Dithane M45 and Bravo.
• Alternating with a copper-containing product will help against bacterial diseases.
•  Small operators should rather use a motorised knapsack for complete coverage.
• A 4 year crop rotation is recommended without growing crop in same family with tomato

Harvesting

• The fruit closest to the branch stem will mature first
• Farmer may to harvest roughly 8-10 weeks in summer and 12-14 weeks in winter from transplanting
• 100-120 tons per hectare