Oct 22 - 28, 2007

It is a useful technology for getting fresh fruits and vegetables at an early stage, for increasing employment opportunities and increasing earning scope.

This technology was first tried successfully in some European countries. Thereafter this concept was adopted in some Asian countries. It has thus been proven that all vegetables and some fruits can be started off in the greenhouse in the shivering cold of the winter in December to February when the temperature is very low as in the province of Punjab when trees, plants and grass are covered with white frost in the open and it is thus impossible to grow vegetables in the open fields. In the case of Punjab, vegetables grown and supplied from Sindh are very expensive and they no more remain fresh and tasty when they are supplied in the market in Punjab due to the time involved in their carriage and transportation all the way from Sindh to Punjab.

Therefore, greenhouse/plastic tunnel farming has been introduced in the extremely frosty winter. Greenhouses are especially designed, as described here under, and are covered with plastic sheets. As a result, the inner temperature is suitably high. Therefore, the plants growth continues inside the greenhouse, while the temperature outside is very low. Ayub Research Institute Faisalabad launched plastic tunnel cultivation in the year 1985. Vegetables are now being grown and harvested in greenhouses over a vast area of land, which include beetroot, carrot, potato, tomato, cabbage, cucumber etc. When all around, there is environment full of frost, shivering cold, strong wind and rain that we cannot control, it is not so in the greenhouse. There is well protected environment within the greenhouse/plastic tunnel, where several vegetables/plants can grow efficiently, of course, under our appropriate care.

BENEFITS OF TUNNEL FARMING: We can not only get early vegetables but can also have a better yield Resultantly, the duration of availability of vegetables increase considerably, which also stabilizes the market prices of the vegetables, besides increasing employment opportunities and alleviating poverty.

Summer vegetables like cauliflowers, cucumber, sweet pepper, hot pepper, egg fruit, bitter gourd, pumpkin, lokey, tomato etc. can be successfully cultivated in plastic tunnels.

Details of tunnels with regard to their structure

1) Tunnel of bamboos: This is a cost saving tunnel but it is not quite durable. A modification in its structure can be made by using small dia white wood upright supports. This would cost about Rs.18,000 and its maximum age limit is 3 years. It means Rs.6,000 per annum.

2) Galvanized iron pipe tunnel: It can be erected with the help of tee iron or galvanized iron pipe. Although its cost is relatively high, it lasts for 15-20 years. However, the cost can be reduced by using bamboos at the roofs. Such tunnels can be moved from one place to another. Although its cost is Rs.43000-Rs.44,000 per kanal, its per year cost is very low.

3) Low tunnel: For arranging this tunnel, angle iron or 5 mm dia bamboos or mulberry tree branches moulded in the shape of a bow can be used. For the purpose branches of 3 meters length can be put to use. In low tunnels cultivation can be done in the month of January. Such tunnels Cost about Rs.5000 per kanal and production can be harvested one month before the normal season.

PREPARING THE SOIL: As the motive behind for cultivation in the greenhouse/plastic tunnel is to get maximum production, the soil productivity should similarly be maximum to get better yield. For the purpose, the most fertile piece of land should be selected about 4/5 months ahead of cultivation and suitable animal manure at the rate of 15-20 tons per kanal be applied. After that a leguminous crop like junter be grown. One month after, this green crop should be buried in the soil by suitably ploughing and levelling. After that soil should be marked for beds (patris). After watering the soil, sweet peppers and cucumber can be sown directly while seedlings of tomato and peppers can be planted.

The scribe had the chance to visit a vegetable model farm known as "Hafiz Farms" on Toba Tek Singh Road in Tehsil Jhang maintained and run on modern scientific lines on an area of 350 acres. Cauliflowers in different categories were grown in white, purple, golden and blue colours. On the scribe's enquiry, it was informed that these special types of vegetables are sent to super markets for use by the high gentry. A variety of vegetables and fruit is grown, which include cucumber, sweet pepper (in yellow, chocolate and green colours), pepper, water melon, egg fruit (green, white and purple), bitter gourd, pumpkin, lokey, strawberry, tomato and cherry tomato, a vegetable of medicinal value for prevention of breast cancer etc.

A documentary was also shown from which it appears that three types of tunnels are used for growing these vegetables using modern technology i.e. high tunnels, walking tunnels and low tunnels. The Manager of the farm informed that tomato yield (grown in the plastic tunnels) last year was 49 tons per acre and this year the production has reached 53 tons per acre. Water melons production was 4 truck loads per acre.

Appreciably, they have also installed processing plants and produce value added products like mixed pickle, cold drinks, namely Malta-Orange, Honey Cola, Eleven-Up and Apple mix. Regarding use of fertilizer, it was informed that E.M. technology was being used, which provides organic type of fertilization. Reportedly efficiency at the farm is 90-95 percent.

Another most appreciable plus point of the owner and the Management of this model farm is that they always welcome the visitors and progressive farmers and do not feel shy to give full guidance for establishing such progressive enterprise in agriculture sector anywhere in the country. That is they do not want to keep these secrets as their business secrets.

With proper use of chemical fertilizers or animal manure, a good production can be obtained by greenhouse farming.

IRRIGATION: Irrigation in extreme hot weather should be made after 3/4 days, while in the winter after 2-3 weeks. Weather conditions should be kept in view for irrigating the farm. It has been observed that in greenhouse/tunnel farming drip irrigation is the most suitable system as it is useful for getting better yield and the tunnels also remain safe from over irrigation by using other methods of irrigation. Moreover, fertilizers are uniformly supplied to the farm, which ensures healthy growth of the plants and better yield. Plastic mulching is also very useful within the tunnel. This protects the crops from unnecessary weeds and their weeding out is no more required. Similarly spading is also not required.

TRIMMING AND PRUNING THE PLANTS: As the number of plants within the tunnel are kept high. instead of allowing them to spread on the bed, they are lifted upward with the help of a string. In the case of tomato, sideway branches are trimmed and pruned so that the central trunk/stem may bear the fruit and the plants instead of flourishing sideway, may use the upward space and light.

POLLINATION: As the tunnel is covered by plastic sheets, flies which under normal circumstances help pollination cannot enter the tunnel and pollination, does not take place. Therefore, in case of some vegetables like turnip and cucumber artficial pollination is arranged. For this purpose when the flowers start blossoming, the pollens of the male flowers are touched with the female flowers. If cucumber is grown in early season, artificial insemination is not required in parethenocarpic type cucumber. Similarly, in case of tomato and hot pepper artificial insemination is not required.

MAINTAINING SUITABLE TEMPERATURE IN THE TUNNEL: The most suitable temperature for vegetables in the greenhouse/plastic tunnel is 15 to 30 C. In order to keep the moisture and temperature suitable within the tunnel, opening/gate of the tunnel should be kept open for sometime during the day. This is also useful for minimizing the attack of the pests and disease. It should be ensured that tunnel should be covered with plastic in such a way that cold wave of winter may not get in so that the heat and warmth obtained during the day could be better utilized at night.