Types of polyhouse

polyhouse are classified on different basis

1. TYPES OF POLYHOUSE

2. POLYHOUSE A polyhouse is a special constructed structure like a building for growing plants under controlled condition. It is covered with a transparent material as such permits entry of natural light. Difference between Polyhouse and Greenhouse……

3. A polyhouse or greenhouse is actually the same thing. Traditionally the greenhouse were constructed on wooden frames where glass was used as a covering material. On the advent of the plastic technology, it become possible to replace the glass with plastic material. As the polythene material, being the most popular the green house came to know as polyhouse in resent time.

4. Types of polyhouse Low cost or Naturally ventilated polyhouses . Medium cost or Partial climate controlled polyhouses . High cost or Fully climate controlled polyhouses Plastic low tunnels Net houses

5. Low initial investment Constructed with locally available material such as bamboo, timber etc. No specific control devices for regulating environmental parameters inside the polyhouse . Suitable during cold weather, especially in hilly areas . LOW COST OR NATURALLY VENTILATED POLYHOUSE

6. The structural frame is made up of galvanized iron pipes . Exhaust fans are used for ventilation, these are thermostatically controlled. Cooling pad is used for humidifying the air entering the polyhouse . These are suitable for vegetable cultivation during mild winter and mild summer for the low hills in NW Himalayas. MEDIUM COST OR PARTIAL CLIMATE CONTROLLED POLYHOUSES

7. Consists of sensors . Frame is made up of iron or aluminum. Designs are dome shaped or cone shaped. These are highly durable, 5-6 times costlier. Growing medium used in these type of greenhouses are Peat, Perlite, Vermiculite, Rock wool. In India coco fibres and rice husks are used as growing media as these materials are cheaper. Fertigation and pesticide sprays are done by fogging machine. HIGH COST OR FULLY CLIMATE CONTROLLED POLYHOUSES

8. Miniature form of polyhouse Protect the plants from rains, winds, low temperature, frost and other vagaries of weather Provide the best way for off season vegetable nursery production by modifying the microclimate around the plants Nursery bed of size 3x1x0.15 m A portable low plastic tunnel of size 3.5x1.20x1.0 m size with polythene sheet of 120 GSM is put on the nursery bed PLASTIC LOW TUNNELS

9. Simple framed structure or small row like structure. Nets of 40 and higher mesh are effective. Control entry of flying insect. Save crop from viral disease. Netting to maintain an environment which also provide isolation from insect borne pollen. Netting allow controlled sunlight for the hardening of new plants taken out from nursery. NET HOUSES

10. Type of polyhouse –Hilly region 1 . Prefabricted polyhouse : A prefabricated metal structure polyethylene film is covered over it. not for all hill- poor temperature retention, low crop yield, and high installation cost .

11. 2. Ladakh Polyhouse Innovative and low-cost - Ladakh region . Difference - its surrounding mud brick wall in place of polyethylene sheets. Reduces the adverse effects of strong winds . Increases net profit . Lean type and has three sides made of mud bricks. The back wall is 7 ft in height, while the front has no wall. The length is 32 ft with a width of 16 ft. The polyethylene is supported on wooden poles and sidewalls. The two sidewalls are descending toward the front.

12. 3. Trench (Underground polyhouse ) Very simple , cheap. Useful underground - hilly region Has unlimited potential . May be of any convenient dimension. Trench of 30 × 10 × 3-ft size is ideal. Polyethylene covered - heat loss(night) winter . Operations- by removing the polyethylene sheet. Adv. Not require much skill -construction and management. Lowest cost. Being an underground structure, heat loss is minimum . Temperature retention is high & yields good crop. Strong winds do not affect polyethylene cover much It is long lasting because of underground. This structure most suitable for the hilly region.

13. Classification on the basis of structural shape of frame Attached : when it is attached or supported by a part of building or any type of constructed wall. Detached : when it is free standing position. Connected : when several polyhouses are joined together in a series.

14. A)   ATTACHED POLYHOUSE

15. b) detached (Freestanding) Structures : Separate structures. They can be set apart from other buildings to get more sun and can be made as large or small as desired.

16. CONNECTED POLYHOUSE

17. Other classifications The polyhouse can also be classified based on type of structures, type of glazing, number of spans, environmental control etc. The various types are as follows. 1.Classification as per type of structure a. Quonset type b. Curved roof type c. Gable roof type 2. Classification based on number of spans. I. Free standing or single span II. Multispan or ridge and furrow or gutter connected

18. 3. Classification as per glazing a. Glass glazing b. Fiberglass reinforced plastic glazing c. Plastic film 4. Classification based on environmental control I. Naturally ventilated II. Passive ventilation

19. Types of polyhouses – shape and sizes Barrel shaped Ridge and furrow type Saw tooth type

20. Site selection A good site can make all the difference in the functional and environmental operations of a polyhouse . The soil should have pH 5.5-6.5 and EC of 0.5-0.7 Mmhs . Availability of continuous source of quality water . The pH of the irrigation water should be 5.5-7.0 and EC between 0.1-0.3 Mmhs . Good supply of electricity . A ground slope for drainage is an important factor to divert surface water way from the poly house. polyhouses should be located away from the buildings and trees to avoid obstruction to sunlight and should be pollution free. Facility of good road transport to near markets. Easy and cheap availability of labourers . Communication facility should available at site.

21. Advantages of polyhouses : The yield may be 10-12 times higher than that of out door cultivation depending upon the type of polyhouse , type of crop, environmental control facilities. Higher production per unit area is obtained. Reliability of crop increases under polyhouse cultivation. Ideally suited for vegetables and flower crops. Year round production of floricultural crops. Off-season production of vegetable and fruit crops. Disease-free and genetically superior transplants can be produced continuously.

22. Efficient utilisation of chemicals, pesticides to control pest and diseases. Water requirement of crops very limited and easy to control. Maintenance of stock plants, cultivating grafted plant-lets and micro propagated plant-lets. Hardening of tissue cultured plants Production of quality produce free of blemishes. Most useful in monitoring and controlling the instability of various ecological system. Modern techniques of Hydroponic (Soil less culture), Aeroponics and Nutrient film techniques are possible only under polyhouse cultivation. Nursery for all vegetable crops can be grown Advantages of polyhouses :…..

23. Plants used in poly house technology are … Floriculture: Roses, Orchids, Gerbera, Aster, Lilies, Marigold, Carnation, Chrysanthemum, Anthurium etc. Vegetables : Mostly exotic such as Asparagus, Broccoli, Brussels, Sprouts, Squash (zucchini), Celery, Cherry-Tomato, Chinese cabbage, Leek, Lettuce, Parsley etc. Landscape Plants: And all types of shade loving plants or foliage plant which require minimum light for healthy growth.  

24. Crops covered under poly house Orchid

25. Crops under Shadenet House

26. Need of Protected Cultivation Higher yield Year round cultivation Better quality Off- season production Assured production Generate self employment for the educated rural youth in the farm sector Least pesticide residues Controlled pollination Vagaries of weather Easier plant protection Weed free cultivation

27. Future Thrusts polyhouse technology development has made good progress in India during the last two decades, and steps necessary for promoting polyhouse cultivation of flower and vegetable crops have been started. Thrust areas for future research are enumerated below: • Conservation of more thermal radiation in winter. • Durable infrastructure modeling. • Development of successful commercial models. • Modernization of polyhouse to permit agroclimatic manipulations of higher magnitude. • Identification of new crops/varieties suitable for cultivation inside the polyhouse . • Socioeconomic impacts of polygreenhouse technology in hilly region/cold arid zone.

28. • Plastic films of suitable grades need to be made available in adequate quantity. • Development of area-specific suitable polyhouse designs. • Standardization of package of practices for growing various crops in polyhouse for specific regions. • Vocational training to the unemployed youth and polyhouse practitioners in remote areas to update their skills in this technology. • Rigorous extension program to disseminate the technology information to the poorest of the society. Future Thrusts:….