adminFarming Matters with Samuel Kadungure
TOMATO is one of the most important and widely grown vegetables in the country. Tomato is one of summer’s most-loved vegetables. It is a warm season crop and therefore sensitive to frost.However, winter has dawned and temperatures have started dropping. Cold temperatures can damage or destroy your tomato plants, but that does not mean that farmers can stop producing them at all. Does that mean we stop eating this fresh treat?
Even in the middle of winter when it is cold and the temperature is near freezing, this solution can work, making it possible to grow tomatoes but with special facilities. Having a greenhouse is one way, but is not essential, as most people do not have one.
After all farmers are encouraged to grow winter tomatoes due to high prices it fetches at the market as supply is far outstripped by demand. The production of tomatoes in winter is lucrative. All farmers must do is ensure that the tomato plants are protected from frost and freezing. Farmers need to be on the lookout for leaf frost as it damages and affects the crop growth. Tomato plants are sensitive to frost and other harsh weather conditions caused by the winter season.
Farmers are reluctant to plant the crop in winter citing lack of special facilities like greenhouses. A greenhouse is a structure where plants are grown and the structures range from small sheds to very large buildings. Greenhouses can be used to improve food production. The concept is now growing currency among small-scale farmers and in Zimbabwe’s urban areas where there is a high demand for fresh produce.
The other reason why most farmers shy away from planting tomatoes in winter is due to lack of knowledge of how it can be done the other way. The farmers also need to know that tomatoes have a high chance of making it as a low rate of disease can affect the plant in winter.
Most tomatoes diseases prefer hot and wet seasons, so in winter there are low or no diseases at all.
Freeze and Frost
A freeze occurs when the temperature dips below 0ºC. Usually a freeze affects an entire region and may last several days. Temperatures associated with a freeze are lower than temperatures associated with a frost.
Surprisingly, tomatoes can survive a light freeze if it is not accompanied by frost, provided temperatures don’t dip below two to zero degrees Celcious.
A frost, on the other hand, is localised. Low temperatures may or may not reach freezing, but moisture must be in the picture for frost to develop.
A frost typically falls overnight but during the following day, temperatures warm.
How does frost develop?
Frost requires clear skies and calm winds in order to accumulate. Heat radiates from the soil, leading surfaces to get colder. Moisture comes into contact with soil and plant surfaces. Moisture crystallizes on the tomato plant, destroying the plant cells when it melts. When damage is severe, the plant dies.
In very dry, cold weather, it is temperatures (not frost) that can damage plants. Cold temps darken leaves and stems. That’s why the condition is called “black frost.”
What to know about protecting tomatoes in a frost
Frost can occur when temperatures are low. Moisture, rather than temperature, is the determining factor. Low-lying areas, where cold air settles, are more susceptible to frost. If your tomato patch is in a low area, pay special attention as temperature dip into zero. Leaf frost can be dealt with through preventative measures such as lighting up fire to produce a cloud of smoke to the tomatoes. This method prevents the frost from accumulating at the plant.
Basic requirements
Basic requirements for growing tomatoes include land, water, tomato seeds or plants, composited manure, trowel or small shovel, twine or any thread for tying plants to supporting sticks or poles.
Ground selection and preparation
Crop rotation is advisable as it diminishes the risk of soil-borne diseases such as early bright and bacterial spot.
Farmers should choose land in an area that receives 8 to 10 hours of sunlight during the day and has good soil and good weather conditions. The area should have decent air circulation.
The ground must be prepared by adding lots of well-rotted composite measuring 25-40kg per square meter. Tomatoes grow well in any warm and fairly damp environments. They can easily be grown organically on soil rich with organic matter.
Seed sowing and plant transplanting
Farmers can start the tomato-growing project from either the seed or plant stage. Several varieties of tomato are advisable as they will provide farmers with a steady harvest. Farmers who prefer to start from the seed stage can buy seeds and sow them 0.5 to 1.5cm under the ground.
Deep sowing may result in seeds failing to germinate. After an average one month the seed will have shot from the ground. They should be transplanted when they reach 15-25cm tall. Given the low winter temperatures, farmers are advised to carry out the project in a Green House. Farmers are advised to transplant other plants three weeks after the first crop to spread the harvest out.
Transplanting
Farmers must bury 50-75 percent of the plant in the soil when transplanting since new roots will emerge along the buried stem. Each plant must be supplied with four litres of warm water within 10 minutes of transplanting to avoid transplant shock. Plants must be spaced 45-90cm apart, although the spacing can be halved in warmer weather conditions. Spacing should leave enough room for the farmer to move in between the plants when weeding, watering and during harvesting.
Irrigation
Irrigation is critical in tomato production. It is important to supply sufficient water at critical times, such as immediately after sowing or transplanting. Excess irrigation after a long dry spell without prior light irrigation results in fruit cracking. During the first four weeks apply 21 mm of water per week, for during the following eight weeks (with 38 mm per week). Plants that are irrigated late in the season produce watery fruits of poor quality. Sometimes it is best not to use an overhead sprinkler irrigation system because wet leaves encourage early and late blight.
Weed control
Weeds can be controlled chemically or mechanically. Chemical weed control can be used by applying registered chemicals. Mechanical cultivation should be shallow and not too close to the plant; this will prevent damage to the plants. Hand-hoeing is also practised, especially with tomato production under protection.
Fertilising
Farmers are advised to adopt Foliar Fertiliser feeding system. The Foliar method involves spraying fertilizer on plant leaves ideally in the morning or evening when the tomato plant pores are open. This facilitates direct absorption of nutrients into the plant. The type of fertiliser should the type that stimulates development of fruit.
Fruit
Tomato fruit will start to appear 45-90 days after transplanting. When the fruit reaches a good size, softness and colour it is ready to be harvested. While the first fruit is ripening, farmers must encourage the development of new fruit by applying manure to the soil and trimming some of the upper leaves.
Picking
The fruit should be picked when it has reached full size and colour. Tomato fruit can also be picked earlier and stored indoors to ripen. This helps lessen their chances of rotting in the field.
Winter tomato produce fetches a high price at the market as supply is far outstripped by demand. Most farmers avoid growing the crop during low temperature seasons due to lack of facilities like Green Houses. Tomato plants are sensitive to frost and other harsh weather conditions caused by the winter season.
Online Reporter