orchids: how to okow them successfully. 21 



Avhon the outside (!onditi()ris of tho atmosphcio ijorniit. But it 

 often hapjjfns tliat it is necessary to shut tlie lious(!S up as closely 

 iis is possible, especially in (ixposod situations, in order to keep 

 the tlierniometer rogistennf? the desired degree of heat ; but when 

 it can be done, admit air through tlu^ bottom ventilators in a very 

 small degree, increasing it if the weather becomes more favourable. 

 In very mild weathei- the top ventilators may be opened on the; 

 leeward side. 



The utmost attention to ventilation is requiied 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 

 ki^pt 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 bhnd early, 

 so that tl)(! temperature may not get too heated, and a little air 

 through the crevices, wliich invariably exist, will be found sufficient. 



SHADING. 



Shading the house sit 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 ^\'ithout some protection in the way 

 of shading. Although most Orchids ]-equire as much Hght 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 downi 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 gi'eenhouse. A framework of wood or iron is 

 fixed upon the roof t)f 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 xviih Cool Orchids, 

 especially during the summer. The blinds can be easily arranged 

 to roll up and down, by means of a cord and a simple apparatus, 



