30 



cember and January, and be as much sheltered from the north and 

 north-west winds as possible. 



Drainage. — It is very important that the most perfect drainage 

 be obtained ; that there be no standing water in any part of the 

 house or near the surface of the ground inside ; that water used or 

 coming into the house shall drain away quickly. Surface drainage 

 should be provided by surface and under-drains about the building, 

 so that during heavy rain storms the surface water shall run away 

 from the building and not toward or into it. 



Water. — Water supply, with a head of at least forty feet, is a 

 necessity for the best results. This should come from cisterns or 

 reservoir and not from wells. 



Construction. 

 Greenhouses can often be built in the country cheaper than in 

 the city, as materials like lumber, stone, etc., can often be ob- 

 tained at a less cost than in the city, and if the owner is at all 

 skilled in the use of wood-working tools he can do much of the 

 work upon the common greenhouse structure. 



Kinds of Greenhouses. 



The form of greenhouse to be built must dejjend somewhat upon 

 the location and the kind of crop to be grown, though the 

 modern greenhouses of all forms are so constructed, with light 

 sash bars and large glass, as to provide ample light, and success 

 with any of them depends more upon the amount of heat supplied 

 and the skill of the grower than anything else. Most of the 

 modern houses for all kinds of crops under glass are lean-to or 

 three-quarters span houses, facing the south, south-east or south- 

 west, though some very good even span rose houses are built that 

 give very good results. 



The simplest structure that would have much value for commer- 

 cial purposes is the lean-to house (Fig. 1). This may be attached 

 to the south side of a stable or dwelling-house, and being sheltered 

 from the north, requires only comparatively little heat, but, on the 

 other hand, cannot be as well ventilated as a house exposed on all 

 sides. 



The three-quarters span house (Fig. 2) facing the south is the 

 one most used by commercial florists and market-gardeners. It 

 possesses the advantage of being cheap in construction, affording 

 the greatest amount of sunshine and may be ventilated from all 

 sides when necessary, for growing crops require low temperature 

 and an abundance of light. 



The foundation of these houses may be of stone or cement or 



