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GREEN HOUSES AND BOTANICAL GARDENS

A greenhouse is an artificial man – made environment that is isolated  from the external surrounding by a transparent polythene paper or glass which only allows light .green houses provide conducive environment for horticulture and for growing other crops and plants that could not tolerate  the climatic and whether conditions of the place  . They also provide physical barriers by which pest and diseases cannot penetrate so as to cause diseases to the crops . The temperatures and other  maximum conditions e.g. water , fertilizers, pest control etc.  provided  inside the green house makes it very conducive for plants  to grow faster and these will  cause them to increase in production

The design of green house requires scientific and specialized workmanship. The size of the greenhouse is related to its function  but it should not be less than  15 x 10 feet because these will cause  serious limitation in terms of managing the excessive thermal changes  cause by sunlight . The size should also allow free movement  of students and other site  for demonstrations and experiments , it should provide space for both  side beds ( and benches)  and center beds

The construction materials for green house include timber frames or aluminum frames  but  aluminum  frames are the most preferred since they don’t rust but they are however expensive. The roofing and the walling materials are made of either transparent polythene or glass but glass is very expensive and delicate. Green houses should be sited  away from nearby  trees so as to avoid unnecessary shades

Green house services

The major services in green houses are water and electricity. They should be adequately provided. The water taps and electric switches should be placed near the door. The electric switches should be waterproof

Green house should have about six water points i.e.

(a)  Water tap

(a) Overhead watering and damping line

(b)  Capillary bench

(c)  Mist propagating bench

(d)  Trickle line bench

(e)  Spare line for  each water point

Green house should also have the following electric services

(a) Tubular heaters

(b) Electric fans

(c)  Small air circulation fan

(d)  Low voltage soil warming cables  for propagation benches

(e)  Electric controller for mist propagation bench

(f)  Two water proof power point  i.e. one at each end of the house for use during experiments

Green house management

Green house management  is sometimes two involving  and sometimes less time could be  available in which to attend  to the green house, to avoid these , provision  of good growing  condition s should  left to  use of automatic equipment’s

A good greenhouse should have good ventilation which will enable free circulation of air which is essential for healthy growth especially during winter since stagnant atmosphere encourage the growth of fungal diseases  . Fans provide necessary air circulation or small air ventilators fixed on the walls.   Ventilation can also be achieved through ventilation openings, which should be about 1/6 of the floor area. Reasonable ventilation control  may be achieved by fitting automatic  devices  which varies  the ventilator openings  with the internal temperature  by  mechanical means.

Heating is done using tubular heaters because they are efficient, safe and convenient. Thermostats should be provided to regulate heating.

Benches should be provided be fitted with small air spaces  left at the back to allow  warm air from the heater  to rise or else cold spots  will occur on benches  which may cause frosting of some plants . Permanent beds may be heated by soil warming cables placed at the depth of 40cm. Soil warming benches are used in propagation benches.

Watering is normally done by means of overhead watering systems, trickle and drip irrigation and by moist propagation benches

Fertilizer application and distribution is done using the Cameron dilutors that is filled with concentrated fertilizer solution then connected to the water supply