The Culture of Greenhouse Orchids 



for a night or two uninjured. 0. crispum succumbs 

 at 13. But this is only a scientific fact, pleasant 

 to recall, when by some mischance the glass shows 

 32 on a winter morning. Assuredly no orchid we 

 cultivate is indifferent to frost. 



During November, December, January, February, 

 and March the night temperature should be 50 

 to 45; during April, May, June, July, August, 

 September, and October, 55; and always the day 

 temperature should be five degrees higher 55 

 and 60. Of course, this ideal cannot be maintained 

 in summer. Even in a lean-to facing the north, 

 heavily shaded, freely watered and ventilated, the 

 heat will rise to 70 or more daily, nor will it fall 

 much below 60 at night. But under the conditions 

 named of shade and water and ventilation not the 

 least harm is done ; neglect of the conditions would 

 be disastrous, however. That must always be re- 

 membered. Upon the whole, too great heat in 

 winter is a much more frequent cause of mischief 

 than summer sun. I repeat that during those most 

 important months November to April when the 

 bulk of the plants are setting and maturing their 

 flowers, 55 by day, 50 by night, are the maximum 

 permissible ; and if the glass begin to fall lower in 

 the small hours, so as to touch 45 at daylight, so 

 much the better. 



34 



