246 Gardening Under Glass 



out in the open, of course, fare all alike as to 

 temperature, those in the house enjoying the 

 advantage over the others of being more thor- 

 oughly safeguarded against fierce heat, squalls, 

 heavy rains, and sudden changes of temperature. 

 During winter, early fall, and spring, when arti- 

 ficial means must be resorted to for adequate 

 supply of heat, conditions are well under control, 

 and a medium degree in temperature, between 

 50 and 60, neither too low for hothouse plants 

 nor too high for the less tender species, may be 

 maintained with gratifying results all around. 

 It should be borne in mind that during that pe- 

 riod growth is sluggish, and the less it is encour- 

 aged by needlessly high temperatiu'es at a time 

 when light and sunshine have lost much of their 

 power as the most active factors in the promo- 

 tion of plant growth, the finer, the cleaner, and 

 the healthier will the plants be when the season 

 of renewed action approaches. 



Ventilation. P'resh air is another important 

 agency that the cultivator may make free use 

 of at almost all seasons of the year. In a prop- 

 erly constructed greenhouse it is easy to provide 

 buoyancy and j)urity of air, to guard against 

 too much or too little, against sweeping cold 

 drafts as well as against atmospheric stagnancy, 

 both being bad for the plants, while with rightly 



