i8 PRESENT-DAY GARDENING 



ture during the day and that experienced at night, the differ- 

 ence in some parts being that between an excessively hot day 

 and a chilly night and early morning. These cool conditions 

 at night are absolutely necessary for the well-being of the 

 plants, and in their absence the plants suffer as do human 

 beings during the progress of a heat-wave, which often kills 

 many people. Therefore it must be urged that at night the 

 temperature must be from 5 to 10 Fahrenheit lower than 

 the day temperatures. This condition is difficult to get 

 during hot weather, but it is necessary. Although a scale 

 of temperatures throughout the year must not be taken to 

 mean that a little more heat may not be allowed occasion- 

 ally as, for instance, by sun-heat, which is beneficial 

 nevertheless it is better to have a scale to form a basis, and 

 especially to emphasise the lower temperature at night. 



Table of Temperatures for Orchid Houses 



Degrees Fahrenheit. The higher day temperature should be obtained by 

 sun-heat when possible. 



