HEATING THE RANGE ', :'101 



nearly as possible the natural conditions which favor 

 its growth. Violets, for example, require a cool, moist 

 soil, therefore they grow best in solid beds. The heating 

 pipes in violet houses should be placed as far from the 

 plants as possible. Sweet peas also grow best in cool, 

 moist soil. One of the largest houses devoted to sweet 

 pea and violet culture is four hundred feet long by forty- 

 three feet wide. The owner has all heating pipes along 

 the sides. The heated air rises until it strikes the roof 

 at the eaves, then continues to the ridge, thus making 

 a blanket of warm air over the plants, and giving sufficient 

 protection from injury by cold, and at the same time 

 allowing a cool condition of the soil. . Fungous diseases 

 are thus kept in check and the heating conditions more 

 nearly approach those from the sun's rays. 



In carnation houses, the larger part of the heating pipes 

 are placed along the sides of the houses. The best growers 

 usually have one pipe underneath the benches. This 

 pipe is so valved that it may or may not be used. It is 

 used in severe weather or when cloudy conditions pre- 

 vail, so that the soil water does not dry out readily. 

 Underbench heat, however, is not satisfactory even in 

 carnation culture, for the bottom soil dries out before 

 the top soil shows any indication of dryness, and the 

 roots of the plants are thus injured. Chrysanthemums 

 require similar temperature conditions to those of car- 

 nations, and intense heating conditions should be avoided, 

 for chrysanthemums are distinctly cool crops. 



Roses thrive best in warm soil and in a warm, moist 

 atmosphere. In rose houses the heating pipes are usually 

 distributed along the sides of the benches. They are 

 rarely placed underneath. 



80. Determination of radiation surface. In an ad- 



