Green House
technology
Introduction
In the present
scenario of perpetual demand flowers, vegetables, orchids and shrinking land holding
drastically, protected cultivation is the best alternative for using land and other
resources more efficiently. In protected environment, then natural environment is modified
to suitable conditions for optimum plant growth which ultimately provide quality products.
Hence in tropical
climate, Green House is an important place where green house or shade-loving foliage
plants are kept. Green House is an artificial constructed shade and covered structures of
plastic film, which allow the solar radiation to pass through but traps the thermal
radiation emitted by plants inside and thereby provide favourable climatic conditions for
plant growth.it is the ultra-mode device used for controlling temperature, humidity, light
intensity, CO2 level inside.If properly constructed, keeping in view the
availability of light and circulation of air, green house may also be used for growing
orchids both epiphytic and terrestrial.
Points to be
considered while constructing green house
- East and south sun is excellent for the
green house, which can remain open on both these sides, but it should be shaded on the
north and the west to protect from winds.
- Construction: A plan should be prepared
before constructing the green house together with plan of beds and paths on the ground.
- Selection of plastic film structure and
roof slope
- Use of proper controlled climatic
condition
- Area and Green house structure
- Plant protection measures
Types of green
houses:
- Tunnel type (cold climate green house)
- Quonset (semicircular/subtropical green
house)
- Gabble type (slopping roof)
- Tropical region green house
- Ridges and furrows green house
- Ground to ground green house
Low-cost
greenhouse/polyhouse
The low-cost polyhouse
is a zero-energy chamber made of polythene sheet of 700 gauge supported on bamboos with
`sutli and `nails. Its size depends on the purpose of its utilization and
availability of space. Like the greenhouse, it has one opening kept azar for 1-2 hr
during the day, especially in the morning to reduce the level of humidity inside. The
temperature within polyhouse increases by 6-100C more than outside. In
UV-stabilized plastic film covered, pipe framed polyhouse, the day temperature is higher
and night temperature lower than the outside. The solar radiations entering the polyhouse
is 30-40% lower than that reaching the soil surface outside.
Medium-cost
greenhouse/polyhouse:
With a slightly higher
cost, a Quonset-shaped polyhouse (greenhouse) can be framed with GI pipe (class B) of 15
mm bore. This polyhouse has a single layer covering UV-stabilized polythene of 800 gauge.
The exhaust fans are used for ventilation those are thermostatically controlled. Cooling
pad is used for humidifying the air entering the polyhouse. The polyhouse frame and
glazing material have a life span of about 20 years and 2 years respectively.
Hi-tech
greenhouse/polyhouse
This type of
greenhouse consists of a sensor, a comparator and an operator. The temperature, humidity
and light are automatically controlled. These are indicated through sensor or
signal-receiver. Sensor measures the variables, compare the measurement to a standard
value and finally recommend to run the corresponding device. For example, temperature
control system consists of temperature sensor, heating/cooling mechanism and
thermostat-operated fan. Similarly, relative humidity is sensed through optical tagging
devices. Boiler operation, irrigation and misting systems are operated under pressure
sensing system. This modern structure is highly expensive, requiring qualified operators,
maintenance, care and precautions.
Advantages of green
house technology:
- Protection from adverse climatic
conditions
- Increase yield 4-5 times than
traditional planting
- Harvesting time can be adjusted
- Off-season crop produce may be obtained
- Disease free plants may be obtain
- More profit due to continuos supply of
produce through out the year
- Water saving as use of drip/sprinkle
system
- Barren and uncultivable land may be
brought under use
- Get more foreign exchange due to export
- Useful technology for hybrid seed
production
- Employment generating technology
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Ag.
Technologies
(Floriculture)
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