Garden Affair: Growing greenhouse tomatoes for profit

14 Sep, 2014 - 06:09 0 Views
Garden Affair: Growing greenhouse tomatoes for profit

The Sunday Mail

tomatoHorticulture is an intensive farming activity that can have great rewards if done properly.

However, when it comes to growing greenhouse tomatoes, it should not be lightly compared to field tomatoes as it is a totally different ball game.

Greenhouse tomato varieties can be effectively grown for as long as ten months without changing the crop, thus the decision to grow this crop must be made soberly as the crop requires daily monitoring.

For a crop grown this long, many things can go wrong indeed.

The key success factor is proper planning and budgeting of time and resources.

Greenhouse tomatoes require a lot of expertise thus a lot of research should be done prior to planting.

Start by selecting a suitable variety and do not be afraid to experiment with new varieties coming into the market.

Greenhouse varieties such as Nemo-netta, Topacio, Gabriela, Florenzia, and Daniela can be grown depending on the resistance of each to pest and disease problems.

The decision to grow the crop in the ground should be done knowing that one can fumigate the soil each time a new crop is grown, otherwise plant the tomatoes in pots or plastic sleeves using pine bark as the medium.

Internationally there is a trend to move away from the use of methyl bromide for fumigation purposes.

Grow your tomatoes on land that has not been used for cropping other solanaceae crops such as pepper, tobacco or potatoes for at least three seasons, or you will have problems with pests and diseases from the previous crops.

Drip irrigation is necessary for both effective watering and fertilisation and plant population in the greenhouse should not exceed 24 000 plants per hectare as anything above the yield from each plant drastically begins to reduce due to nutrient and disease factors.

Plant tomatoes at in-row spacing of 35cm-50cm apart and an inter-row spacing of 90cm-140cm for easier spraying, supporting, desuckering and harvesting.

Consult an irrigation specialist for the best equipment for fertigation depending on the size of your plot.

Install at least two injectors for fertigation purposes which will allow you to add a blend tomatoe fertiliser rich in potash and also calcium nitrate at the same time separately.

These two fertilisers cannot be mixed as they will react forming lumps which will clog the irrigation system.

The fertilisers are added at every watering time mixing at lower concentrations in the drip lines.

These solutions translate to a dilution rate of 100 parts to one (200 parts per million), enough to supply two-fifths of a hectare.

This mixture is adequate for plants which are already bearing. When starting a new crop, use half this amount and gradually build up to this level. Irrigate the crop prior to fertigation.

There are different injectors that will supply nutrients at different rates in parts per million.

Depending on the fertiliser type used the farmer can calculate how much fertiliser to add per hectare.

Soil pH and EC levels need to monitored during the entire life of the crop. Soil pH measures the acidity or alkalinity of the soil whilst EC measures the soluble solids in the soil which are an indicator of nutrient deficiency or excess. EC levels for most crops range from 0,75 to 1,25 whilst pH for tomatoes must not exceed 6,2.

Greenhouse management requires that the farmer makes daily decisions about diseases and pests.

Failure to act decisively could spell huge losses for the grower. Well trained scouters are essential to constantly monitor when to spray for a particular pest or disease before it reaches an unmanageable threshold.

Major pests to look out for in greenhouse tomato production are the white fly, red spider mites, cutworms, nematodes, aphids and thrips with control ranging from proper sanitation, preventative spraying programs and destroying infected plants.

Serious diseases of tomatoes are early blight, bacterial wilt, bacterial canker, mildews and leaf spots. Preventative sprays work best.

Ensure that minimum foliage is kept on the plants removing all lower dead leaves and any old leaves.

Greenhouse tomatoes need a support system that will withstand the weight of the crop when it begins to fruit.

Tomato marketing needs to happen well before the crop is in the ground both locally and internationally.

The investment in greenhouse structures can bring huge capital gains only to the farmer who is willing to spend long hours in the field.

 

Contact Andrew Mangwarara for further information by email on [email protected]

Share This:

Survey


We value your opinion! Take a moment to complete our survey

This will close in 20 seconds