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AgriQuora . 20th May, 2021

Ultimate Guide to Growing Tomatoes

Tomato farming is quickly becoming a common practice among many farmers and gardening lovers. Despite many challenges in this farming niche, farmers are not relenting.

Tomato is one of the crops that can bring lots of rewards to the farmer. It is a high-value sub-tropical vegetable crop that comes in different hybrid varieties available to farmers.

The common varieties in Kenya are: Anna F1, money maker, Mavuno F1, Marglobe, Kentom – these are fresh varieties. But there are also the processing varieties such as Cal J, Riogrande, Roma VF, Parma VF, Rubino among others.

Most farmers grow tomatoes in their gardens for home use. But tomato can also be grown on large scale for commercial purposes.

Different varieties have been optimized for field or greenhouse production. You can check out this list for a suitable variety for your agro-ecological zone.

Nutritional Benefits of Tomatoes

Tomatoes contain carbohydrates, fiber, vitamins (Vitamins C, K1, B9) and minerals mostly potassium. And the major compound in this crop is lycopene although there is also beta-carotene, naringenin, and chlorogenic acid.

Lycopene exists in large proportions in tomato products like ketchup, tomato juice and tomato-based sauces.

Nutrition Facts: 100 grams of ripe, raw tomato contains the following;

Component Proportion
Calories 18
Water 95 %
Protein 0.9 g
Carbs 3.9 g
Sugar 2.6 g
Fiber 1.2 g
Fat 0.2 g
Saturated 0.03 g
Monounsaturated 0.03 g
Polyunsaturated 0.08 g
Omega-3 0 g
Omega-6 0.08 g
Trans fat ~

Source: Healthline

Here are more specific benefits associated with tomatoes.

  • Heart Protection

Tomatoes contain the lycopene compound which helps in scavenging of high density lipoproteins (HDL). The HDL pose a risk of heart attack and stroke.

  • Good Vision

Vitamin A helps in improving the vision of an individual and prevents night-blindness.

  • Skin Health

According to this study, lycopene in tomatoes and other compounds have been shown to reduce sunburn incidences. One study found 40% reduction when combined with olive oil.

  • Cancer Prevention

Studies have shown that tomato consumption reduces the risk of prostate, stomach, and lung cancers (see this and this). These positive attributes have been attributed to high lycopene levels in tomatoes.

In fact, another study has shown that this powerful component can reduce the risk to breast cancer in women as well.

  • Digestive Health

Tomatoes are rich in fluid and fiber that will help recondition your gut, especially if you are prone to constipation.

  • Managing Diabetes

Consuming tomatoes in diet reduces lipid peroxidation. Lipid peroxidation is a chain of reactions that leads to formation of free radicals.

Presence of free radicals in the system exacerbates the risk to heart disease, which is a major scare in diabetes type II.

Ecological Conditions for Tomato Growing

It is important to consider the following factors when you want to grow tomatoes.

 1. Site

The site should be located closer to the water points for ease of watering the plants.

When the water-points are located further from the growing field or greenhouse, the cost of production is going to rise. The reason for this being the additional costs associated with pumping water from long distances.

2. Soil Requirements

Tomatoes do well in deep, fertile loam soils that are free from pests and diseases. The soils should be easy to work on, well drained and able to support the plants effectively in their whole life cycle.

The greenhouse soils should be sterilized to eliminate any traces of pathogens that may show up during the growth of the plant.

The pH value of 6 to 7 will be great for the crop.

3. Temperature

Given that tomato is a sub-tropical plant, it requires warm temperatures to grow well. It should be noted that the plant is very sensitive to frost.

The mean average temperatures needed by tomato are between 20-24 degrees Celsius daily. This results to optimal growth of the plant – enhancing the yield and quality of the fruit.

4. Topology

The land for tomato growing should have a gentle slope. This is vital in facilitating proper drainage so that water is not pooling in the field, especially during the rainy season in open field production.

5. The Previous Cropping

Tomatoes should not be planted on the fields which previously held pepper, potatoes or other same family crops.

This helps in the control of the most common and notorious diseases troubling the tomatoes.

Tomato Production: Routine Management Practices

1. Nursery Management

  • The nursery should be prepared up to the finest tilth. This is important for the ease of planting the tomato seeds.
  • The nursery should have the standard width of 1 meter. A raised nursery is preferred.
  • The sowing lines should be 2-3 cm deep and 2 cm apart.
  • After sowing, the nursery should be covered with a thin layer of dry grass or gunny bags.
  • Watering should be undertaken gently after the mulch has been applied.
  • Remove the grass/mulch after 4 days: the plants should have germinated after this period.
  • Watering should be conducted daily – morning hours and in the evening when the sun’s gone down.

2. Transplanting Tomatoes

The seedlings should be ready to be transplanted 4 or 5 weeks after the germination has occurred. At this stage, the seedlings have about 5-6 leaves.

  • There is need to irrigate the nursery and field before, during and after transplanting has been done. As usual, planting should be done in the early morning or late evenings, the time when irrigation is also carried out.
  • Spacing for the tomato plants should be 60 x 60 cm, which is the standard spacing requirement.
  • Plant the seedlings on the ridges made on the field.
  • Ideal plant population in the greenhouse is and 8,000 to 10,000 when planted in the open field.
  • Only healthy seedlings are planted to ensure a healthy start in growth.

Tomato Production: Field Management Practices

1. Fertilizer Application

Application of phosphate fertilizers should be done at the base of the tomato plant. This encourages vigorous root development.

The plants should receive urea at 2-3 weeks to facilitate proper leaf development and vegetative growth.

Again when the plants start flowering, they can be top-dressed using NPK. After the first harvest, the farmer should apply NPK to increase the yield.

All fertilizer applications should be based on the soil analysis of the field.

The recommendations are based on the nutrient removal by the tomato crop.

Nutrient Removal in Kg by 1 tonne of Tomato Yield/ha and Acre (For P and K given as atom and salt)
Yield/AreaNP2O5   PK2O  K
1 t/ha30.80.354.53.7
1 t/acre1.250.331.151.901.5

Source: Sygenta

2. Watering

The tomato plants need to get adequate water at all points of growth. This supply, however, should not be excessive or leaching of nutrients down the soil horizon is going to occur.

Sustainable irrigation methods should be used especially the drip irrigation.

3. Staking

The practice of staking is very important for the health of the tomato plants hence high productivity. There are more fruits of higher quality produced.

Staking involves the process of using poles or sticks on which the growing tomato plants are tied vertically. This is done to provide support to the weak tomato stems.

The young plants should be staked a few weeks after planting in the field to help them grow normally and avoid any breakages of stems.

4. Pruning

Pruning of the tomato is vital. This helps the plants to grow well and increase its productivity.

Prune the diseased and old leaves; side shoots and even laterals. Other target areas should be the suckers at the joints between two tomato branches.

A lot of care is required to avoid injuring the plant. It can lower the productivity if done carelessly.

5. Weeding

Since there will be weeds in the field, regular weeding is recommended. Weeds compete with the young tomato plants for essential growth aspects like light, moisture, nutrients and even space.

If they are left, plants will grow slowly, weakly and overall productivity is greatly affected.

Tomato Pests and their Control

The tomato plants are afflicted with a number of pests and diseases that are of serious economic importance. These normally affect the plant growth and overall crop yield.

Here are the major pests:

1. American Bollworm

The larva of this moth is very destructive to the tomato. They appear brown or green and sometimes pink. So the larva attacks the tomato fruit by boring tunnels in it and sucking the juice.

2. Tobacco / Tomato White Fly

This one can kill the leaves of the plant by sucking the sap. In the process, they can even transmit viral diseases.

Control of the two pests named above can be done through the application appropriate insecticides.

3. Gram Pod Borer 

The causative agent is Heliothis armigera. It is a polyphagous pest which attacks most cultivated crops. The young larvae feed on tender foliage, while adult pests destroy the fruits. They bore holes on fruits.

4. Serpentine Leaf Miner 

This is also a polyphagous pest. Its maggot burrows and feeds on the mesophyl of the leaves leaving a sepentine gallery on its tracks. The causative organism is Liriomyza trifolii.

5. Tobacco Caterpillar

Caused by Spotoptera litura, also a polyphagous pest. Its larvae feed on leaves from the ventral side. They feed on foliage mostly at night.

6. Root-Knot Nematode

Caused by Meloidogyne spp. The nematode inhabits a variety of hosts, making it a dangerous pest for many vegetable crops. They are microscopic. The males are slender while the females have a club-like swelling.

They produce root galls in affected plants. The sick plants exhibit slow growth, leaf chlorosis, wilting, and reduced fruit development.

The common tomato diseases and their control:

tomato, vine, garden

Here are the most common diseases in tomatoes.

1. Early Blight

First observed as small, isolated, pale brown spots on the leaf, which then spreads to the stem and fruits. Fully developed spots are brown with concentric rings inside the spot. The causative agent is Alternaria solani.

2. Late Blight

The causal agent for this disease is a fungus. The disease causes dry patches on the leaves and fruits of the plant.  Use suitable fungicides and other husbandry practices such as crop rotation to control the late blight.

3. Damping Off

Caused by either Pythium aphanidermatum or Rhizoctonia solani. Young seedlings are killed before they emerge through the soil. The grown up plants rot around the collar.

4. Bacterial Wilt

Deadly tomato disease caused by Pseudomonas solanacearum. It causes wilting, stunting, and yellowing of the foliage. The lower leaves droop first before wilting starts. The plant finally collapses.

5. Tomato Mosiac Virus

The disease is caused by a virus and manifests as mottled leaves.  The mottling is seen as interspersed light green and/or pale yellow patches. The leaf edges curl downward and become stiffer than a healthy leaf.

This disease also affects tobacco and cucumbers.

6. Powdery Mildew

Caused by Leveillula taurica and exhibits as a powdery substance covering on leaves. Lesions may occur on the lower surface of the leaf. Heavily infested leaves eventually die but usually remain attached to the plant.

7. Septoria Leaf Blight

Numerous spots are observed on older leaves or plants with poor growth. They start as small circular spots (usually on the underside of the leaves) on water soaked areas. The spots then enlarge, sink in, and develop dark brown color with white or grey centers.

The disease is caused by Septoria lycopersici.

8. Black Mold Rot

Observed as flattened water soaked lesions on the fruits which then darken. It is caused by either Alternaria alternata or Stemphylium botryosum.

It usually happens to tomatoes that come into contact with the soil where they are attacked by soil-borne fungi that causes rotting of the fruits.

9. Fusarium Wilt

If the wilt is caused by Fusarium oxysporum sp. Lycopersici, the disease manifests as leaf chlorosis, then the petiole and leaves droops and wilts. There is a discoloration of vascular tissues (you will observe a dark brown color when you split open the roots and basal stems.

Control is through uprooting the infected plants and destroying them. Planting in containers can really help to prevent the bacterial wilt. Use certified seeds too.

9. Blossom End Rot

Blossom End Rot (BER) causes the fruits of the plants to rot at the blossom end – the place appears water-soaked. Actually, BER is not a disease but rather a condition or disorder.

The condition comes about as a result of the calcium imbalance in the plant.

Ensure that the plants receive enough moisture.

General Disease Management Strategies in Tomatoes

ultimate tomato production guide
  • Practice crop rotation. Alternate legumes with solanaceae.
  • Solarize the soil ad burn trash on the surface to destroy pathogens.
  • Pinch off yellowing leaves and dispose far from the crops.
  • Uproot heavily infested plants. Do not put the diseased pile in the compost pit.
  • Ensure the soil is well drained.
  • Avoid working in the garden when the plants are wet.
  • Avoid wetting the foliage when irrigating.
  • Mulch the crops early in the season. Mulching helps keep the soil moist and prevents splashing of fungal agents during rains.
  • Keep the plants properly spaced to facilitate air circulation and light penetration.
  • Use recommended chemicals according to the agronomist's recommendations.

Harvesting of Tomatoes

The tomato fruits will be ready after about 3 months from transplanting. The tomatoes for canning should be harvested when they’re fully ripe.

Those that are intended for the fresh market are supposed to be under-ripe. All fruits need sorting and grading (in terms of color, size and other qualities) before they are packed and transported to the market.

Marketing of Tomatoes

Only high-quality tomatoes should be transported to the market. During transportation, care should be taken to avoid damage.

Therefore, quality of transport should not be compromised.

They should be transported in specially designed crates to avoid injuries to the fruit.

The characteristics of good quality tomatoes include: clean, fresh, whole, undamaged, not deformed, free of foreign materials, not rotten, no abnormal moisture, firm consistency among others.

In Conclusion

Tomato farming can come with many demands. But the benefits are even bigger when farming is done for commercial purposes.

It is vital to be aware of the different varieties available in the market. Choose the fast growing and early maturing varieties.

Mastering the production procedure from nursery establishment to land preparation, planting, maintenance, and marketing is important for a serious farmer who wants to make it in this enterprise.

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