GREENHOUSE TOMATO PRODUCTION

 

Greenhouse Tomato Production has in recent times being the best way of producing tomatoes with better performance and a good quality yield. This tomato is of high value and costs more than the field tomato because of the relative cost of establishing a greenhouse.

However, as easy as greenhouse farming may sound to some people, there are some important things we must take note of before venturing into greenhouse production of tomato;

1.      Greenhouse tomatoes have cultural requirements unlike other crops, such as field tomatoes. It requires different management practices from any field-grown crops.

2.      Greenhouse tomatoes need timely and special attention for it to be successful.

3.      It required more labor per unit basis than any field crops. Thereby making it to be more cost and labor intensive.

4.      As some people do believe that greenhouse is free from problems this is however not so because of the special treatment needed by greenhouse plants.

Furthermore, the varieties of tomatoes planted in the greenhouse are different from that of the field. The greenhouse tomato varieties are indeterminate hybrid tomatoes that can grow well under high relative humidity and lower light, unlike the field varieties. However, for a Greenhouse to be fully ready and functional for tomato production, some devices must be fully installed in it. These devices are discussed below:

·         Irrigation facilities: this consists of the bulk tank, pump, hose and pipes that supply water and soluble fertilizer to the plants in the greenhouse. It is the most important component of the greenhouse. The capacity of this facility must be able to feed the greenhouse with the required quantity of water regularly.

·         Thermostat: This is a device that is used to measure the relative humidity in the greenhouse. It is placed in a box to prevent direct contact with the sunlight at the center of the greenhouse. The optimum relative humidity of 60-70 percent must be maintained in the greenhouse.

·         Thermometer: This is used to measure the temperature in the greenhouse. It is a must have for a farmer because too low or high temperature may damage the plant.

·         pH meter: this is used to monitor the pH of the water to be supplied to the plant. For tomato production, the pH must be between 5.6 and 5.8 anything higher or lower will cause injuries to the plant. Nitric acid and sulphuric acid can be used to lower the pH; nitric acid is the best because it also supplies nitrogen. While on the other hand, bicarbonate or limestone may be used to increase the pH to the required level.

·         Electrical conductivity meter: this device is used to monitor the nutrient status of the fertilizer supplied to the plants. It helped to measure the rate of fertilizer to be applied to a plant.

·         Ventilation facilities: the condition in the greenhouse is mostly warmer than the surroundings hence a cooling system is needed to bring the temperature down to the optimal level. And when the temperature in the greenhouse is lower some other day, it is used to raise the temperature. This facility helped in temperature regulation in the greenhouse.

·         Pollinating devices: tomatoes on the field are pollinated mostly by wind or insects but, for those in the greenhouse where the wind is very weak to cause pollination alternative measures should be adopted. Tomatoes that are not well pollinated will give poor fruits and yields hence the need for alternative pollinators in the greenhouse. There are two ways we can achieve pollination in the greenhouse: one is by the use of electric pollinator and the other the use of Bumblebees.

GROWING MEDIUM FOR TOMATO PRODUCTION

Generally, the production of any crops in the Greenhouse requires a growing medium unlike the conventional field crop production where crops are planted on the soil. Therefore, there are two main types of growing medium used for the production of crops in the greenhouse:

 Soil culture medium: this involved growing of the tomatoes in soil medium. The soil is either pack into nursery bags and arranged in the greenhouse or the soil in the greenhouse is made into beds where the crops are planted. Whichever way, this is cheaper than the soilless medium however we will discuss the preparation of this medium below:

•   Collection of fertile topsoil from areas around the greenhouse.

•   Collection of weathered organic manure preferably poultry manure.

•   The fertile topsoil and manure collected are sterilized in the sterilization chamber. The sterilization chamber is a rectangular container where the medium is subjected to intense heat for a few hours to kill harmful microorganisms in the soil.



Soil medium greenhouse tomatoes

•   The medium is allowed to cool for some hours before it’s packed into black nursery bags then they are arranged in pairs into the greenhouse.

Soilless culture medium: NFT (nutrient film technique), PVC pipes, troughs, and rock wool slab. It may also be referred to as hydroponics where nutrients are supplied directly to the plant roots through pipes, wool and the likes. It is more cost-intensive and required more technical-know-how to operate efficiently.

Meanwhile, other materials used for growing medium include cocoa pit, coconut husk and so on.

soilless growth medium

OPERATIONS IN A TOMATO GREENHOUSE

             The tomatoes to be planted in the greenhouse are first raised in the nursery for 21days before they are transplanted to the greenhouse. Prior to the transplanting to the greenhouse, the bags containing the growth medium are irrigated for 2-3days to soak them up; for soil growth medium. The tomato seedlings are then transplanted to the greenhouses in the morning or late in the evening and they are supplied with water and fertilizer. The application of nutrients and supply of water to the tomato plants must be timely and adequate for proper growth and development of the plant.

Transplanting and plant spacing: the tomato plants are transplanted from the nursery into the greenhouse when they are three weeks old and water is supplied to them. During transplanting the plants are evenly spaced to allow proper growth of the plant. For a greenhouse with nursery bags, one plant is planted per bag.

Irrigation: this is the most important operation in the greenhouse it is the supply of water and nutrients to the plant. After the tomato plants have been transplanted into the greenhouse, water supply should be regular and even when the plants have established fully. Inadequate supply of water will cause the plants to wilt when the plants wilt they stop growing and if they are not still supplied water to resuscitate, the plants will reach the permanent wilting point. At the permanent wilting point, the plant dies and no amount of water given can revive it. Therefore, the supply of water must be timely and adequate meanwhile, the supply of water with fertilizer is termed Fertigation. Water is supply to the base of the plants: contact of water with the leaves must be as much as possible reduced or avoided to prevent fungal growth.

Fertilizer application: unlike the field tomatoes that rely either partly or wholly on the nutrients from the soil, greenhouse tomatoes need to be supplied artificial nutrients to survive. In the greenhouse, there are two ways to supply nutrients to the plants, these are; the Bulk tank and Injector methods. For the Bulk tank, the fertilizer is added to the irrigation water and is supplied along with the water to the plants; fertilizers used here are mostly water-soluble. For Injector method, the fertilizer is supplied to the individual plant through an injector and this is more labor-intensive.

Furthermore, it is important to note that only the required amount of fertilizer must be applied to plants; under-application will slow down the growth of the plant while over-application will cause injuries to plants. The electrical conductivity meter is used in measuring the requiring quantity of fertilizer for plants, it is measured in Mho however, PPM is best used to measure nutrients quantity. The table below shows the amount of fertilizers required by tomato in a greenhouse;

Nutrients required	Ppm in solution at 100 % strength
N (nitrogen)	171
P (phosphorus)	48
K (potassium)	304
Ca (calcium)	180
Mg (magnesium)	48
Fe (iron)	3
Mn (manganese)	1-2
B (boron)	1
Zn (zinc)	0.4
Cu (copper)	0.2

Pruning and Training: Pruning is the removal of the excess branch to the tomato to bring out good yield. Pruning affords the tomato plant to channel the energy used in producing more branches to giving good fruits. Also, the number of fruits per cluster on a tomato plant can also be reduced to two or three to allow for the formation of bigger fruits.

Training is the stacking of the tomato plants to keep the plants upright and also to be able to withstand the weight of the plant thereby preventing lodging when the plant start to fruit. The tomatoes are trained on a parallel string above the tomato in the greenhouse.

Next we will discuss some precautions to be the taken in the greenhouse and also look at some diseases and nutritional deficiencies of greenhouse tomatoes