The tomato is the edible berry of the plant Solanum lycopersicum, commonly known as the tomato plant.
Tomatoes are loaded with a substance called lycopene. It gives them their bright red colour and helps protect them from the ultraviolet rays of the sun. In much the same way, it can help protect your cells from damage. Tomatoes also have potassium, vitamins B and E, and other nutrients.
You also need to think of the cost of the production, seeds, fertilizers, and other pest and disease control chemicals against the price you are likely to get for your crop.
You need to talk to your local Agritex officer for advice on the cash crop you intend to grow. The Agritex officer’s advice must be taken into account before choosing a crop to grow.
When these factors have been taken into account you need to plan when you want your crop to reach the market.
This guideline provides details of the key steps for the establishment and production of a tomato crop by individuals, enterprises and/or community groups.
Uses
Fresh fruits are used in salads and cooked with relish. Cultivars grown for processing are canned and made into purees, sauces or juices.
The nutrient content of the fresh per 100g is as follows:
Water 93ml, calories 21, protein l g: fat O.2g; carbohydrate 4g, fibre O.6g; plus minerals and vitamins.
The Tomato Growing Calendar
Sowing Time First Fruit Ripening Peak Harvest
January April/May May/June
February May/June August
March/April July-August August/September
May September October
September/October January/February February/March
November/December February/March March/April
Avoid sowing in the cold winter months in areas prone to frost. Your local extension worker will advise on the appropriate dates to plant and what protective measures to take during periods of frost.
Below are the stages of crop growth. These stages are affected by temperature, cultivar and moisture levels.
• Germination will take 7-10 days.
• From emergency to transplanting 4-6 weeks
• Plants should be transplanted when approximately 10-12 cm tall
• From transplanting to first flowering 4 to 6 weeks
• From first flowering to first fruit ripening 4 to 6 weeks
• Harvest period can vary from 10 to 15 weeks
Establishing the Crop
• Tomatoes should be grown in a nursery first before transplanting to the field.
• Tomatoes grow well on well-drained soil
Seeds must be obtained from a reputable source and must not have expired or near expiry dates. Expired seeds may not germinate or if they germinate may produce weak plants which may not produce the best fruits or high yields.
Preparing the Seedbed
Choosing a seedbed site:
When choosing a nursery site consider the following points.
• Choose a site far away from any related crops to reduce the risk of disease and pest transfer.
• Select a site that had not been under tomato or a related crop for the past three seasons to avoid disease and pest attacks.
• Select a site with medium to light textured soils that are deep and fertile.
• Select a site with well-drained subsoil to reduce water logging.
• Select a site closer to a permanent water source.
• Choose a secure place preferably closer to a homestead.
Sterilization of the soil
This soil should be sterilized to kill pests and diseases that affect the crop. You can sterilize your soils by burning stalks inside the seedbed before planting. This should reduce the nematodes and other soil-borne diseases of tomatoes.
Making the seedbed
Peg the area first then dig the area and thoroughly level it. Make ridges so that water won’t flow out when watering.
Fertilizing the seedbed
You can add manure or fertilizer. Mix manure with topsoil. You can broadcast about 3 kg of compound D in your nursery bed and mix. Water the bed.
Sowing the Seeds
Planting
Mark furrows 1 cm deep and plant seeds every 4 cm in the row. Leave about a 7 to 10 cm distance between rows and cover the seed with fine sand. Approximately 120-170g of seeds will be enough for one hectare. This should give approximately 14,000 plants per hectare when transplanted.
Watering
Water the nursery twice a day Iightly for the first week in the morning and afternoon. Then once a day in the second week and once every two days in a third week until transplanting this will harden the seedlings before transplanting.
Mulching
Cover the seedbed with grass to retain water and also prevent excessive burning of seed by the sun.
Weeding
Pluck out weeds in the nursery bed by hand.
Transplanting the Seedlings
Tomato grows well in a variety of soils provided they are deep, well-drained and fertile. Avoid growing tomatoes after eggplants, tobacco and related crops. It is susceptible to frost so grow it in warm areas during winter.
The best soils to use are our deep fertile black, red or brown clay loam, sandy clay or sandy loam on a gentle slope. Avoid grey or white sandy soils in veils and on steep slopes.
Preparing the Land
Land should be prepared as soon as the seed is sown in the seedbed to allow decomposition of organic matter: late land preparation will lead to seedlings overstaying at nursery level, making them overgrow and in worst cases, flowering takes place in the nursery bed.
Plough the land or dig with a hoe up to 20 cm deep. Apply well-decomposed organic manure at 10 to 20t/hectare 3 weeks before transplanting and mix well with the soil.
• Manure builds soil structure by glueing the soil particles.
• Manure is cheaper
Apply Compound Cor S at 400kg/hectare when making planting stations. If irrigation is to be used construct furrows/ridges spaced 1m apart. If irrigation is to be done using watering cans, make long raised flat beds with a width of 1m. Beds are raised to ensure good drainage and aeration, especially in the rainy season. Water the furrows or beds thoroughly.
Transplanting
Transplant seedlings when they are 4-6 weeks from emergence approximately 10-12cm tall. Select healthy seedlings only. Transplant during the morning or evening when it is cool or on a cloudy day.
Other factors to consider when transplanting tomato seedlings are:
• Do not leave roots exposed (ensure that some soil is kept on the roots) or put them in a sack so that the roots are in damp soil.
• Ensure that there is firm contact between the soil and the roots
• Do not plant the tomatoes in the furrow irrigation is to be used
Apply wood ash after transplanting to protect transplants against ants and termites. It also acts as fertiliser, supplying potash, which is responsible for fruit quality.
Transplant during the morning or evening when it is cool or on a cloudy day,
Watering
Water immediately after planting and every 4-5 days after that. When plants are fully established water once every seven days but increase watering from flowering onwards. The amount of water can be scheduled as follows:
• Transplanting to establishment-up to a depth of 6cm every 4 day
• After establishment, increase to 8cm depth per week till maturity.
Top Dressing
Apply ammonium nitrate at the first stage of flowering at a rate of 100kg/ha when fruits are marble size, at every three weeks intervals. Place the fertilizer 5cm from the plant. Water the crop to allow this fertilizer to dissolve.
N.B. Do not place the fertiliser on the plant because it will kill the plant.
Tendering the Crop
Trellising
Trellising is done to prevent tomato plant lodging which can result in loss of fruit due to disease and rodents.
There are three methods for trellising.
• Single stake – place the stake along one side of the row and tie plants to the stake. This is suitable for the home garden.
• Single wire tied between two poles to the end of each row. Place wire at 0.5m intervals. Three wires will be enough to keep plants standing. In between support poles can be spaced as needed. Plant lodging can decrease the quality of the fruit and also yield. Plants can also be
susceptible to disease.
• Double wire – Pairs of wire on each side of the post are placed at intervals up the pole.
• The plant is supported between wires and three sets are required at 0.5m intervals.
Removal of buds and shoots
Removal of side shoots to encourage single-stem growth is not recommended. Removal of lower branches and leaves is not recommended.
Hygiene
• Sterilize equipment using 2 per cent formalin if the disease is present.
• Forbid smoking or taking of snuff in the field
• Ensure personnel wash their hands before entering the seedbed and field
• Discard diseased seedlings
Harvesting
A yield of between 75-100 tonnes/ha is possible
There are four distinct stages of picking depending on the intended markets
• Pale yellow blossom end – the fruit will last a week or more before ripening depending on the cultivator
• Pink blossom end – the fruit will ripen in 4 days or more
• Pink stages – the fruit will ripen in one or two days
• Ripe stage (fruit ripe but firm) market or use immediately.
Grading
• Remove diseased fruits
• Arranging according to size, colour, ripening stage
Packaging
Pack fruit in the same grade separately. The most ideal is a wooden box (50x23x15) cm usually weighing 5.5 kg for table tomatoes.
For long-distance transportation wooden boxes must be used. These boxes usually weigh 20kg when full. Do not overfill the boxes as tomatoes may be crushed if bearing the weight of the top boxes.
Storage
Ripe tomatoes can be stored in a shade for 8-10 days
Marketing
Tomatoes can be sold to villagers, local markets and urban centres. Try your local grocery shop you may find a ready market.
Pests and Diseases
Common pests and diseases
It is recommended to ask your area AGRITEX representative about which control measures to take when pests or disease is observed in the field. This way you are guaranteed to get the best control measure available and alternative. AGRITEX representative will know which chemicals are available and which chemicals are no longer suitable or in use in Zimbabwe.
Bacterial Canter:
Wilting foliage, mealy breakdown internal tissues of the stem with separation from the pith. Brown horseshoe-shaped area seen when leaves are cut off flush with stem small sports on fruit usually with a white or yellow halo Correct seed and site selection should eliminate the problem Soil on whIch a diseased crop has been grown becomes contaminated can transmit Infection to subsequent crops. Seed borne. First observed In ZImbabwe in 1960 and is now wider spread. If cancer does not occur on the land the grower should preferably select seed from his own crop rather than buy It.
Bacterial Spot
Dark brown raised pustules on the fruit, later becoming slightly sunken & scabby; leaf spot Correct seed selection copper oxychloride sprayed at a rate of 0.4kg/100-litre water Seed-borne infection only occurs during the wet weather
Bacterial Wilt
Sudden wilting of plant browning of woody tissues from which bacterial-drained soil slime oozes after cutting across the
main root & lower part of stem Plant on well-drained soil Widespread in Eastern Districts, but seldom serious
Virus Mosaic
Mild strains cause a light dark green mottling of the foliage. Plants infected early may become stunted, but infection after the crop has become established on land normally has little influence on growth. Blotchy ripening of the fruit may occur.
b) Severe stains cause stunting, leaf curling, and purpling of the veins; severe brown markings sometimes appear on the fruit Remove and burn infected plants. Plant-resistant cultivar Substantial loss has occurred as a result of strains
Bunch Top shoot elongation Causes a marked reduction in resulting in leaves at the top of the plant small and distorted Remove and burn infected plants Outbreaks are sporadic but can cause failures. As insect vectors may be involved
Fungal Botrytis Rot
Green fruit is generally attached.
A small water-soaked spot appears on the stalk end or on the side of the fruit. The spot enlarges, becomes soft and dirty, light grey to brown in colour and fruits turn soft. Also, Ghost Spot and Leaf Stem Rot Spray with dicloran 50% up at a rate of 150g/100 litres water Spray stem to a height of 450-600mm and from February, repeat every 7 days if necessary
Collar rot
Dark-brown sunken lesions on the stem of seedlings and young transplant at soil level Spray with sulphur mancozeb (48/32% wp) at a rate of 500-800g/100 litres water Full cover spray and repeat at 5/10 day intervals in humid conditions with same fungus as Early Blight. This disease is common at all times of the year
Early Blight
Dark reddish-brown leaf spots with concentric markings appear first on the lowermost leaves; causing defoliation. Infection of the fruit is usually around the calyx but may be associated with cracks and other skin injuries Several chemicals are available. Mancozeb 80% up at a rate 200/100 litres water can be used
Which is the best season to grow tomatoes in Zimbabwe?
Best grown in summer between August and April. Cutworms, Red Spider Mite, White Fly, Bacterial Wilt, and Early and Late Blight are the common pests and diseases.
Which fertilizer is best for tomatoes in Zimbabwe?
Another important nutrient to pay attention to is potash, especially for vegetables that produce fruits (tomatoes) or tubers (potatoes). For these crops top dressing with potassium nitrate fertilizer will help generate better-quality produce.
Are tomatoes profitable in Zimbabwe?
Tomato farming in Zimbabwe remains lucrative. It is undoubtedly one of the agribusinesses that can spill in cash all year round. Starting a tomato farm is easy. All it requires is seriousness and one will discover that making money is not difficult after all.
Which tomato seed is best in Zimbabwe?
Roma VF. This is a very popular variety in Zimbabwe. It matures mildly early and is also well-suited for processing. The plant type is determinate and has a strong heavy cover.
What diseases affect tomatoes in Zimbabwe?
The five crop pests and diseases cover Tuta absoluta, Fall Army Worm (FAW), fruit fly, maize lethal necrotic diseases and banana fusarium wilt.