A Shadehouse is a structure enclosed by agro nets or any other woven material to allow required sunlight,moisture and air to pass through the gaps. It creates an appropriate micro climate conducive to the plant growth. It is also referred as shadenet house or net house.

The shadehouse structure should be planned taking into consideration the type of crop to be grown, locally available materials and local climatic conditions. The provision for future expansion should be there.

A shadehouse should be located in such a way that it is well connected with market for input supplies and sale of its produces. This structure should be constructed away from buildings and trees, so also away from industrial or vehicular pollutants. The site should be free from drainage problem. There should be provision of electricity and good quality water. However, wind breakers may be located 30m away from the structure.

There are mainly two criteria for shadehouse orientation. They are, the uniformity of light intensity in the shadehouse and wind direction. Single span structure may be oriented either in east-west or north-south direction but multispan structure should be oriented in north-south direction to ensure uniform light intensity.

A shadehouse structure composed of two basic components i.e. frame and cladding material. The shadehouse frame provides support for cladding material and designed to protect against wind, rain and crop load. The shadehouse mild steel (ms) angle frame lasts upto 20 to 25 years, if anti rust treatment is done at regular interval, whereas bamboo structure can last upto 3 years. The agro shadenet lasts for 3 to 5 years depending on the climatic condition. Shadenets are available in different colours with wide range of shade percentages viz. 25%, 30%, 35%, 50%, 60%, 75% and 90%.

The design of shadehouse frames depend on the need and engineering skill. Structural frames of quonset, gable or gothic arch shape or with minor modification suitable to local condition are recommended in high rainfall areas like Orissa.

Two types of shadehouse designs have been developed at Precision Farming Development Centre, Orissa University of Agriculture and Technology, Bhubaneswar. The principal advantage of these shadehouses is that these structures do not require any welding at the site. Another advantage is that foundation posts have been chosen to protect these structures against termite attack. The details of these shadehouses are mentioned below :

This design (Fig. 1) makes use of ms angle (35mm x 35mm x 6mm) and bamboo as structural frame. The ms angles are used as foundation posts with provision for grip at the bottom and ‘U’ clip for holding bamboo at the top. Bamboo is used both as purlin and roof structure. The levelling of shadehouse site is done followed by layout of the plan. The digging of pits for foundation posts are done, a portion of pits are filled with sand and compacted well. Then foundation posts are fixed with cement concrete, maintaining proper alignment in three parallel rows. After proper curing, bamboo sized to proper dimension is used as purlin, roof arch structure (hoops) and are tied properly. Pre-fabricated end frame and door frame are fixed to the structure with nuts & bolts. Then agro shadenet of 50% - 75% is fixed to the roof and nets of 30% are fixed to the side frame. The in end frames and door are also covered with shadenet. Lastly mid-pavement and boundary ridge line is constructed with brick masonary.

This design (Fig. 2) makes use of ms angle (40mm x 40mm x 6mm) for foundation posts, purlins, end frame and door of shadehouse structure. The ms flat is used for hoops to support the cladding materials. The foundation posts are having provision for fixing with purlin and hoops by nuts & bolts. Similarly ms flat used as hoops are having provision for fixing with purlin. The levelling and layout of plan at site is done as in previous case. The foundation posts are fixed to the pits with cement concrete and curing is done for seven days. The fixation of purlin, hoops, end frame and door frame are done by using nuts & bolts.

Then nets are fixed to the structure. Lastly mid-pavement and boundary ridge line is constructed with brick masonary. The unit cost of this type of shadehouse structure is Rs. 500.00 /Sqm. The materials used in this type of shadehouse are shown in table 2.

The shadehouse structures are getting popular in the state like Orissa where hot summer hampers the plant propagation work. There is also provision of incentives for farmers by National Horticu lture Board and National Horticulture Mission. In this context two shadehouse designs elucidated here will be helpful for construction of shadehouses.