ORCHIDS : HOW TO GROW THEM SUCCESSFULLY. 25 



but only rarely during the winter or spring should they be opened on 

 the windward side. 



The utmost attention to ventilation is required during the spring 

 months, as the plants are then in a somewhat tender and delicate state, 

 having passed through the winter, when, no matter how much care 

 may have been exercised as to heat and ventilation, they are of 

 necessity deprived of much air, having been kept in a close temperature, 

 and are therefore more susceptible of a check at this season than at any 

 other period. It is then we often get bright sunshine accompanied 

 by a cold east wind, when it is a mistake to open the ventilators, as 

 many do, to keep down the temperature. Instead of doing this let 

 down the roller blind early, so that the temperature may not get too 

 heated, and a little air through the crevices, which invariably exist, 

 will be found sufficient. 



Ventilation at night requires careful management and it is always 

 beneficial at night, when the outside condition permits, as well as 

 during the day in our uncertain climate, with the exception of the 

 Cool Orchid house, which we can ventilate as freely at night as 

 during the day. 



In the Intermediate house in warm weather I frequently leave on a 

 good deal of bottom air, and sometimes a little on the leeward side at 

 top ; and in warm weather a little bottom air in the Warm houses, but 

 very rarely leave on top ventilation during the night, especially in the 

 growing season. No hard and fast rule can be laid down, so much 

 depends upon the cultivator's own judgment, for not only do the 

 conditions of structures vary, but also the climatic conditions in various 

 parts of the country, even when not far apart. 



SHADING. 



Shading the house at all times, when necessary, is another subject 

 to which I must draw attention, as some Orchids do best in the shade, 

 many prefer partial shade, whilst others, in their native state, luxuriate 

 in the full blaze of the sun, but, when under glass, there are few plants 

 that will withstand its full power during the summer months without 

 some protection in the way of shading. But as most Orchids require 

 as much light as can be given to them, exclusive of the scorching rays 

 of the sun, it is best to use roller blinds that can be let down in sunny 

 weather and rolled up during cloudy periods or when the heat of the 

 day is past. One of the best systems of shading is that marked D and 

 E on illustration of a model Orchid house. A framework of wood 

 or iron is fixed upon the roof of the house, merely for the roller to rest 

 upon. This framework should be about eight inches from the glass, so 

 as to admit air and keep the house cooler than if the shading rested on 

 the sash bars, an important point with Cool Orchids, especially during 

 the summer. The blinds can be easily arranged to roll up and down, 



