20 GREENHOUSE CONSTRUCTION AND HEATING. 
are termed ‘“‘hard-wooded” plants (including the heaths or 
ericas, with epacris, azaleas, boronias, and others) in par- 
ticular must receive abundance of light and pure air at all 
times. 
As putting the matter in a still more plain and concise 
form, the following may be useful :— 
Tomatoes succeed best in wide and lofty houses, very - 
light, and abundantly ventilated ; much artificial heat being 
unnecessary, except for early crops. Structures 20ft. to 
Fig. & 
30ft. in width and proportionately lofty, with a moderately 
steep pitch of roof, are now usually employed for this crop 
(see Fig. 7). 
' For Cucumbers, low, close houses, with moderately flat 
roofs, are best. They must be fitted with brick beds on 
each side (if span-roofed), with hot water pipes running 
along the bottom of each, as shown in Fig. 8. Cucumber- 
houses always used to be constructed 12ft. in width, but 
