29 



particularly if the outside conditions are severe ; but the greater the 

 fire heat used, the more moisture is required to temper it. 



There yet remains temperature to be considered. The great desi- 

 deratum to be aimed at is equability. Different orchids require diffe- 

 rent temperatures, and it is common practice to speak of a cool, an 

 intermediate, and a stove house to suit their requirements. If one 

 strikes a mean between a cool and an intermediate house it is surpris- 

 ing how many orchids can be grown together and flourish. During 

 the past year I have endeavoured to give an average daily summer 

 temperature of 65 , irrespective of sun heat, and a winter temperature 

 of 55 , falling to 48 , and occasionally to 44 or 45 at night. I have 

 had Odontoglossum, Cattleya, Masdcvallia, Lcelia and Oncidium 

 grow and flower vigorously. If the night temperature never falls 

 below 50 it is almost possible to grow anything, provided the air 

 is dry, and even Odontoglossum, the coolest of epiphytes, does better 

 if a 50 minimum is aimed at. Cattleya and Lcelia doubtless do 

 better with a slightly higher temperature generally, but it is possible 

 to grow and flower them in the same house with Odontoglossum. 

 An ideal Odontoglossum temperature is 50 in winter and 6o° in 

 summer ; and to anyone starting the growing of orchids I should 

 recommend Odontoglossum. Very little need be expended in fire 

 heat, and they are not so impatient of dull winter days as are 

 some others. The ideal method of heating a greenhouse is un- 

 doubtedly by hot-water pipes with a gas boiler, as the gas can be 

 regulated with every change in the weather. I have used gas with 

 complete success but it is admittedly expensive. A small coke 

 furnace can be run at a quarter the cost, and a house of twelve feet 

 by nine would not cost more than a couple of sovereigns per annum 

 to heat sufficiently for Odontoglossum if coke were used and one 

 always did his own stoking. 



There are many other practical sides of the question of growing, 

 but I fear I have detained you already too long. 



