Tomato growing guide-the greenhouse way

Tomato is one of the most highly consumed vegetable in Kenya. It is grown for fresh market, processing and export market.

The information covered here includes:

•     Ecological Requirements
•     Tomato Varieties
•     Husbandry practices
•     Pests and nutrients disorders
•     Diseases
•     Harvesting and Post Harvest Handling
•     Marketing, Gross margin and Value addition

Ecological Requirements

Tomato is fairly adaptable and grows well in warm conditions. It requires optimum temperatures of 20 -25 degrees C during the day and 15 -17 degrees C at night.

Requires moisture of about 600mm well distributed throughout the growing season.

Requires well drained soils, light loam with high organic matter content and pH of 5 -7.5

Tomato Varieties

Fresh market

•     Money Maker
•     Marglobe
•     Beauty
•     Kentom 1
•     Kentom 2
•     Capitan
•     Tropic

Processing

•     Cal J
•     Roma VF
•     M – 82
•     Riogrande
•     Rubino
•     Parmamech
•     Parma VF
•     Nema 1401
•     Picardor
•     Spectrum

FRESH MARKET VARIETIES

Money Maker

1.     Fruit weight 75 gm
2.     Maturity period 67 days
3.     Yield 32 – 50 tons per hectare
4.     Susceptible to diseases

Marglobe

1.     Fruit weight 170 -180gm
2.     Maturity period 67 days
3.     Yield 32 – 50 tons per hectare
4.     Susceptible to disease

Beauty

1.     Fruit weight is about 80gm
2.     Maturity period approximately 70 days
3.     Average yield is 20 tons per hectare
4.     It is susceptible to disease
5.     Usually grown  for fresh market and processing

Kentom 1

1.     Fruit weight is about 100 gm
2.     Maturity period approximately 65 days
3.     Average yield is 65 tons per hectare
4.     It is resistant to nematodes
5.     Usually grown  for  fresh market

Kentom 2

1.     Fruit weight is about 120 gm
2.     Maturity period approximately 70 days
3.     Average yield is 65 tons per hectare
4.     It is resistant to nematodes and bacteria wilt.
5.     Usually grown  for fresh market

Capitan

1.     Fruit weight is about 100 gm
2.     Maturity period approximately 74 days
3.     Average yield is 67 tons per hectare
4.     It is Resistant to some strains of bacterial wilt.
5.     Usually grown  for  fresh market

Tropic

1.     Fruit weight is about 230 gm
2.     Maturity period approximately 74 days
3.     Average yield is 68 tons per hectare
4.     It is susceptible to disease
5.     Usually grown  for fresh market

Principles of Green House Technology:
A greenhouse (also called a glasshouse) is a building where plants are grown under controlled micro environment. These structures range in size from small sheds to very large buildings. A miniature greenhouse is known as a cold frame.

A greenhouse is a structure with different types of covering materials, such as a glass or plastic roof and frequently glass or plastic walls; it heats up because incoming visible solar radiation (for which the glass is transparent) from the sun is absorbed by plants, soil, and other things inside the building.

Air warmed by the heat from hot interior surfaces is retained in the building by the roof and wall.

Purpose of the Green House

a)      To promote tomato growing in the cooler areas
b)      To promote the growing of tomatoes throughout the year in both cool and warm areas
Justification of the Green House Tomato Growing
a)   Growing tomatoes in a green house reduces disease infection and also raises the temperature. Tomatoes require an optimum temperature range of 20-25 0C during the day and 15-17 0C at night.
b)  In the green house, tomatoes may be fed with carbon dioxide easily. This increases yield and enhances quality.
c) Currently, most farmers grow tomatoes during the dry seasons, under irrigation.

In the green houses tomatoes can be grown all the year round

Advantages of a Green House

a)      Higher yields can be realized/intensive production per unit area
b)      High quality produce
c)      Minimized cases of diseases
d)     Market timing for optimum profit
e)      Production levels may be maintained all the year round
f)       Other warm season crops may be grown throughout the year

Other Crops Recommended in the Green House

a)      Coloured Capsicum  varieties  e.g. red, yellow etc.
b)      Cucumbit family e.g. Cucumbers, courgettes
c)      Onions e.g. bulb onions,
d)     Garlics
e)      Herbs and Spices  e.g coriander, parsley, celery
f)       Brinjals (egg plants)

Location of a Green House:

Factors to consider while locating green house;

a) Sunlight direction: The greenhouse should be located where it gets maximum sunlight. The first choice of location is the south or southeast side of a building or shade trees. Sunlight all day is best, but morning sunlight on the east side is sufficient for plants. Morning sunlight is most desirable because it allows the plant’s food production process to begin early; thus growth is maximized. The next best sites are southwest and west of major structures, where plants receive sunlight later in the day. North of major structures is the least desirable location and is good only for plants that require little light.
b) Light requirements of the plants to be grown;

c) Shade: Evergreen trees that have foliage year round should not be located where they will shade the greenhouse because they will block the less intense sun.

d) Drainage: Good drainage is another requirement for the site. When necessary, build the greenhouse above the surrounding ground so rainwater and irrigation water will drain away. Access to the greenhouse should be convenient for both people and utilities.

e) A workplace for potting plants and a storage area for supplies should be nearby.

f) Prevailing wind
g) Topography of the area

Basic Structural component of a green house:

Framing materials:
Greenhouses may be constructed from several different materials. Among the most popular are aluminum, steel and wood. Of these three, aluminum is by far the most economical and longest lasting.
Covering materials:

Greenhouse coverings include long-life glass, fiberglass, rigid double-wall plastics, and film plastics with 1- to 3-year lifespan. The type of frame and cover must be matched correctly.
Size

(1 Bank/Bay/Unit Dimensions:- ( 15 m x 7 m (or 50 ft x 23 ft)  =  105 m2 or 1150 ft2 ( minimum economic unit)

No. of Plants: -400-600 plants, depending on spacing.
Requirements:

(i) Polythene (Gauge 1000 Ultra Violet (U.V) treated).

•     Walls (sides) - 4m x 48m
•     Wider roof - 6m x 16m
•     Narrow roof - 5 m. x 16m.
•     gables - 6 m x 9m
•     Door shade - 4m X7m

Inputs

(i) Labour - for construction, digging trenches, mixing planting medium, leveling and crop management
(ii) Seeds - 5gms (1000 seeds)
(iii) Fertilizers - 10kgs DAP, 10kgs    CAN and 10kgs CN for top dressing.                Foliar feed - 2 litres or 2kgs
(iv) Insecticides and fungicides

• Insecticides - systemic (1 litre) and
• Contact (1 litre) at harvesting
• Fungicides - Preventive (1kg) and
• Curative (1kg).
• Alternate preventive fungicides with curative fungicides for effective disease control and to avoid disease resistance.

Crop Management in the Greenhouse:

Nursery Establishment

a)      Green house varieties:-
Anna, Arleta, Nemoneta, Monset,  Monyala, Ken Tom etc
b) Construction of germination boxes

• Measure boxes of 100cm (length) x 45cm (width) x 10cm (depth)
• Fill the first 5cm of the box with small stones (2 inches) followed by 2cm of sand and then 2cm of forest soil mixed with well rotten manure or use the already mixed growing medium
• Mix the forest soil/growing medium with a handful of DAP fertilizer and Nematicide to control nematodes.
• Make drills of 8cm apart, leaving 5cm from both edges of the box. This gives 10 lines/box
• Plant 50 seeds per line (to give 500 seeds/box). 2 boxes are required per green house unit.

c) Nursery Management

After sowing, cover the seeds with a thin layer of soil or sisal bag and water immediately

Water twice a day, early in the morning and late in the evening for the first 2 weeks Reduce watering in the third week to harden off the seedlings

Transplanting

• Transplanted at 3 weeks.
• Water the beds. Transplant late in the evening or early in the morning on a cloudy day
• Dig holes at 50cm x 30cm in zigzag or alternate (in tandem)=400 plants or 33cm x 30cm= 600 plants per green house
• Apply 20gms per hole (1 tablespoonful) of DAP/TSP/DSP and mix thoroughly with the planting medium to avoid direct contact with the seedlings. The fertilizer may be applied three days after transplanting. Water thoroughly after fertilizer application.

Note: When transplanting spray with Preventive fungicide such as Dithane M45, Milthane Super, Sancozeb,  etc.

After transplanting, initial watering should be mixed with a curative fungicide to eradicate any fungal manifestation e.g. Ridomil,  Equation Pro, Galben, Milraz, Acrobat etc.
Training/trellising

A strong wire 10-14 gauge is placed parallel to the row of plants from one end of the house to the other at the height of the posts (3 m) from the ground.

Sisal twine is tied around the stem base of the plant, which is then trained to achieve 8 - 12 trusses of tomatoes.

Dibudding/De-Suckering:

Done early to remove side suckers or branches to leave one stem only per plant.

Bud Nipping:-

To get healthy and uniform fruits remove apex or growing bud when plant achieves 8-12 trusses (to remove apical dominance)

Leaf Trimming and Defoliation

This is cutting of leaves and removal of excess leaves in order to avoid bushy plants, which reduce fruit growth.

Top Dressing:

Apply 20g of CAN per plant, 2 weeks after transplanting and 20g CN (Calcium Nitrate) 2 weeks later to encourage vigorous growth.

Thereafter apply foliar feed at 2 weeks interval to provide micronutrients.

Husbandry practices

Planting in a nursery

•     Make fine tilth seedbed
•     Drill seeds in rows 15 - 20cm apart, 7cm between seeds and 1 cm deep.
•     Keep soil moist but not water logged.
•     After germination thin to 7cm apart in a row to ensure strong seedlings.
•     Note that the seed rate in a nursery is 150 to 200 gm/ha.

Transplanting

•     Space holes1m by 0.5 m to get a population of 20,000 plants per Ha.
•     Apply manure at a rate of 2 handfuls per hole and mix thoroughly.
•     Apply 1 tea spoon per hole of DSP or DAP (this is equivalent to 200kg /Ha).
•     Transplant about 1 month after germination when the seedling has 4 – 6 true leaves

Planting medium

-Sawdust/Sand/Manure at the ratio of 3:1:1  Or Top soil/sand/manure at ratio of 3:1:1

Direct sowing

•     Space holes 0.75-1m between rows and 0.5m between plants.
•     Apply manure at the rate of 2 handfuls per hole and mix thoroughly.
•     Apply 1 teaspoon per hole of DSP or DAP (this is equivalent to 200kg/ha)
•     Direct planting seed rate is 800 to 1000gms per hectare

Caring for the crop

Top Dressing

•     Top-dress at 4 weeks after transplanting with CAN at the rate of 100kg/ha
•     Four weeks later top dress again with a compound fertilizer or a recommended foliar feed.

Mulching
Maintain mulch especially for determinate varieties (It keeps the fruits clean, suppresses weeds, conserves moisture and keeps soil temperatures low)

Weeding
Weed regularly (Weeds compete for nutrients and also act as hosts for diseases and pests)

Irrigation
Irrigate the crop 2 – 3 times a week during dry weather

Staking

•     For tall growing indeterminate varieties
•     Push a 3m long stake firmly into the ground next to each plant.
•     Train the stem loosely to the stake as the plant grows
•     Use suitable training material e.gbanana twine.

Pruning

•     Pruning is necessary for indeterminate varieties.
•     Allow one or two main stems to grow per plant.
•     Pinch off all other lateral shoots once a week.
•     When the plant forms 6 to 8 trusses, pinch off its growing top.
•     Remove leaves close to the ground to prevent entry of blight.

Pests & Nutrient disorders

Nutrient Disorders

• If the fruit has a hollow cavity and has poor taste, it might be due to potassium deficiency.
• If the crop demonstrates stunted growth, delayed maturity and reduced yields it might be due to phosphorous deficiency.
• If the crop show blossom end-rot it might be due to excess Nitrogen or Calcium deficiency.
• If the crop show blossom end-rot and small size fruits it might be due to excess Nitrogen.

For nutrient disorders refer to your extension officer to get further advice

Pest Diagnoses

• If there is swellings on the roots causing stunting of the plants and eventual wilting this is possibly due to Root Knot Nematodes
• If there is sign of caterpillar damage characterized by bore into fruit and consumed inner part of the fruit with plenty of excreta, this is possibly due to American Bollworms
• If you see small white moth-like flies fly from foliage when plants are disturbed.  Or notice leaf distortion and stunting this is possibly due to Tobacco White Fly.
• If minute spider like animals are found on the underside of the leaves.  The leaves are tarnished and turned yellowish and whitish.  If infestation is severe plants show stunted growth, leaves dry up and falls off. The pest is possibly Red Spider Mites.
• If you notice plant lice that sooty mould and distorted young leaves and flowers the problem is possibly due to Aphids

Root Knot Nematodes

Symptoms: These include swellings on the roots causing stunting and yellowing of the plants and eventual wilting.

Control

•     Crop rotation.
•     Plant nematode free seedlings that is with no swellings on the roots.
•     Keep field free of weeds.
•     Use recommended nematicides

American Bollworms
Symptoms

•   The caterpillar bore into fruit and feed on the inner part of the fruit releasing plenty of excreta which is noticeable on damaged fruits.
•     The entry point of the caterpillar acts as entry point for bacteria and fungi.
•     It attacks sweet pepper, tobacco, sorghum.

Control
    Use recommended insecticides

Tobacco White Fly

Symptoms

•     Small white moth-like flies fly from foliage when plants are disturbed.  The nymph sucks sap from underside of the leaves.
•     They transmit virus.
•     They cause leaf distortion and stunting if attack is early.

Control

• Keep field free of weeds
• Use recommended insecticides and spray the underside of the leaves.
• Spraying should start from periphery moving towards the centre. Early morning or late in the evening.

Red Spider Mites

Symptoms

• These are minute spider like animals found on the underside of the leaves feeding on the sap.
• Whitish to yellowish specks cover the leaf surface. Under severe infestation fine webs will be found covering the leaf surface, there is also stunted growth, leaves dry up and falls off.
• The problem is acute in dry areas or irrigated crops.

Control
    Use recommended miticides.

Aphids

Symptoms

• These are plant lice that suck sap from leaves causing leaf distortion especially during dry spells.
• Aphids prefer young leaves, stems or flowers.
• Their secretion causes sooty mould.  They transmit viral diseases.

Control
    Spray with recommended insecticides

Leaf minor

Symptoms

A small caterpillar that burrows between the top and lower leaf lamina creating silvery tunnels on the upper leaf surface causing considerable damage to the leaves.

Control
Spray with recommended systemic insecticides

Diseases
Disease Diagnoses

• If leaves dry rapidly and fruits show brownish dry-rot eventually destroying the whole crop, the disease could be late blight
• If seedling stem cankers and dark brown spots form on the leaves causing possible defoliation that expose fruits to sun scald, The disease could be early blight
• If leaves have tiny brown black angular leaf spots with possible defoliation the disease is possibly Septoria leaf-spot streaks on stem and fruits show attack severity.
• If leaflets of the lower leaves wilt and curl and dried whole leaves curls upwards, turn brown wither but remain attached to the stem. If the stem split open and the pith is often discoloured.  Or if young fruits show discolouration of vascular system, they show deformation and stunting on mature fruits birds eye spots are visible the disease is possibly Bacterial Canker.
• If there is yellowing and wilting of the lower leaves with slight dropping at high temperatures. If the vascular vessels also appear brown, which is restricted to the stem near the soil level, while roots show a severe browning and decay. The disease is possibly Fusarium Wilt.
• If irregular dark green spots appear on the foliage which eventually dries or blossoms drop. Or initially a small spot appears on the fruit which eventually enlarges. The disease is possibly Bacteria spot.
• If you see a rapid wilting of plants, large number of adventitious roots that are produced on the stem. The pith showing brown discolouration the disease is possibly bacterial wilt

Blossom End-rot

Symptoms

• An early sign of the disorder are a water soaked spot near the blossom end of the fruit.
• This turns brown and enlarges to cover almost half of the fruit.

Possible causes

• Too fast growth during the early stages followed by sudden drought especially when the fruits are small.
• Excessive nitrogen and infrequent watering.
• Calcium deficiency especially in young fruits.
• Low application of nitrogen to calcium deficiency soils

Control

• Application of CAN
• Apply calcium chloride foliar feed at 15kg/1000 liters (Higher concentration will damage leaves).
• Lime calcium deficient soils.

Late Blight

Symptoms
Occurs under cool and high humidity conditions especially wet season.
It is characterized by rapid drying of leaves and brownish dry rot of fruits often destroying the whole crop.

Control
    Spray with recommended curative fungicides.

Early Blight

Symptoms

• It occurs during hot weather.  It causes stem cankers on seedlings and small irregular dark brown spots on the leaves.  As they enlarge they show a concentric pattern.  The result is partial defoliation of the crop.
• It causes premature fruit drop and low quality fruits.
• It is soil borne and the fungus usually survives on plant debris.

Control

• Field sanitation.
• Crop rotation.
• Spray with recommended curative fungicides.

Septoria leaf spot

Symptoms

• Disease occurs at all stages of the plant.
• It attacks the solanaceae family and survives on plant debris.
• Its development is favoured by wet weather.
• It is characterized by the presence of tiny brown black angular leaf spots on leaves.  The spots can cause defoliation, which then exposes fruits to sun scald.  In severe attacks, lesions appear on stems and fruit stalks.

Control
Spray with recommended curative fungicides.