88 orchid-grower's manual. 



VENTILATION OF ORCHID HOUSES. 



HIS is of great importance ; for if cold air is allowed 

 to pass among the plants they will not thrive, and 

 all care which has preyiously been bestowed on 



them will be in vain. Means of ventilation should therefore 

 be provided near the ground, close to the hot-water pipes, in 

 order that the air may be warmed on entering the house ; 

 and also by underground pipes, so that in cold weather a 

 current of pure air may be maintained. This can be accom- 

 plished by lajdng drain-pipes from the outside under the 

 foundation to the inside under the hot-water pipes, so that 

 the air is warmed immediately upon entering the house by 

 passing over the heated sui-face. In the houses here, there 

 are three ventilators in the brickwork opposite the pipes on 

 each side to each house. The ventilating shutters are made 

 of wood, about two feet long, and one foot wide ; sliding 

 slate ventilators answer perhaps better. There should be 

 one glass ventilator at the south end, near the roof, and 

 one at the north end. We have also four small ventilators 

 near the top of the roof, two on each side, on hinges, 

 opening from the inside with cords, to let out the top-heat, 

 which we have found very essential to the well-being of the 

 plants. 



SHADING. 



VERY Orchid house requires to be shaded, although 

 we are often told the practice is wrong ; but as the 

 plants would soon be destroyed if the burning rays 

 of the sun were allowed to shine upon them when grown 



