How to Build a Low-cost Poly-house
- Problem: protection of young vegetable seedlings from pest infestation, heavy rains, drought and cold weather.
- Idea: Arch shaped small greenhouses made from bamboo and polyvinyl sheet
- Difficulty: Wind stability, fungal attack due to high humidity
- Price Range:
- Material Needed:
- Geographic Area:
- How Many people?
- How Long does it take?
The idea of a low-cost poly-house came to our mind in 2004 when Pradan initiated the implementation of land and water-based livelihood activities in the Mayurbhanj Team, with support from India Canada Environment Facility (ICEF). One of our major focusses, in this project, was to increase family incomes by providing individual irrigation infrastructure to each family through the construction of small farm ponds (average size 40 x 50 ft) and dug wells. Our most successful intervention, in terms of addressing land-based livelihoods, was pond-based agriculture. Within three years of the project, 570 families in 11 villages benefitted from the construction of 500 ponds and 25 dug wells. This intervention really changed the cropping pattern of the area from mono-crop paddy to vegetable cultivation on a large scale. An awareness of the change that had taken place was best expressed by a man in a local market, “Aji kali Karanjia re panipariba Pradan pain sabudine milu paruchhi” (Now-a-days vegetables are always available in Karanjia because of Pradan).
- Constraints in vegetable cultivation:
The climate of Karanjia is best suited for vegetable cultivation. The temperature starts falling from July onwards. People prefer to grow cole crops such as cabbage and cauliflower in early kharif, which starts from end of July.
Karanjia has good market linkages with Jamshedpur in Jharkhand and the coastal areas of Orissa. Middlemen from Jamshedpur and Anandpur in Keonjhar district and other coastal areas come directly to Karanjia to buy vegetables such as cabbages, cauliflowers, pumpkins, etc. In a season, farmers earn Rs 8,000 to Rs 10,000 through the sale of these cole crops. However, the nurseries for these cole crops often suffer due to heavy rains and to insect and pest infestations. This leads to losses and disappointment among the farmers.
To surmount these problems, our team initially thought of building portable poly-houses for individual families. We had been taught the concept of poly-house in the agriculture colleges that some of us had attended. A poly-house is a structure made of polyvinyl sheet. It is low-cost because the wood and bamboo and other materials used, barring the polyvinyl sheet, can be found locally.
The advantages of a poly-house are several. Plants can be grown as per the requirement, irrespective of the weather conditions, because it is a closed structure. The covering of polyvinyl sheets protects seedlings from insect and pest attack to a great extent, ensuring the production of healthy seedlings. Plants grow faster inside the structure because the temperature remains a little higher inside the poly-house, even when it is cooler outside.
Our team first made an arch-shaped bamboo frame covered with polyvinyl sheets. The frame was used to cover the bed and could be lifted for irrigation. One poly-house covered one bed with a capacity of a 1,000 seedlings. Initially, the farmers were excited about this structure. However, they faced some problems with this design. Strong winds blew away or damaged the portable polyvinyl cover because it was so light. Second, owing to the small enclosed space and height of the poly-house, there was an increase in the humidity and temperature inside resulting in the damping off of young seedlings. Damping off is a common fungal disease, which attacks seedlings, weakening the stems at the soil level. Infected seedlings usually die. Third, the frequent lifting of the frame for irrigation, and its being blown away occasionally by wind, resulted in the seedlings being highly vulnerable to infestation by pests.
Our team then designed a structure, 5 ft high, that covered two nursery beds, so that during irrigation there would be no need to lift the frame. The attempt was to ensure that it would not be easily blown away by the wind; the humidity would be less and, therefore, there would be lesser chances of the damping off of young seedlings; and the beds could be irrigated without lifting the structure, thereby limiting the entry of insects and pests. However, this structure too got damaged in very windy conditions and the humidity could not be controlled much due to poor ventilation. These experiences lead the team making further changes in the design of the low cost poly-house.
Plans and Illustrations
Seedlings of Success
Umakanta Khandei, a graduate of Patbil village, who lives with his six-member family, was trained by the Mayurbhanj team to function as a Village Level Expert (VLE) for the Land and Water Development Samiti in the Hindusahi hamlet of Patbil. The close exposure to the activities being carried out by the hamlet-level association, under our project with ICEF, kindled his entrepreneurial spark. He decided to take up intensive vegetable nursery farming, using improved practices. With our guidance, he built a 600-sq-ft poly-house, investing about Rs 11,000 (2009), to provide greenhouse cover for vegetable seedlings. He grew 40,000 quality vegetable seedlings in one batch, free of infestation by insects and pests. The production of seedlings in the poly-house took lesser time, that is, 15-20 days, than the usual 20-30 days. The produce was assured, even if there were adverse weather conditions such as rain and very low temperatures. Farmers from Patbil and the nearby villages now purchase seedlings from him. He earns about Rs 1,500 per month from this. He has also started raising cashew seedlings. In the second year of the project, he earned about Rs 15,000 from selling cashew seedlings. He now plans to branch out into producing various horticulture saplings such as mango, drumsticks and so on.
This Article was initiated by papori 2 sept 2009.
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