166 THE PRINCIPLES OF FLORICULTURE 



them. This equalizes the heat, and moisture from the 

 bench is not dried out. 



Soil moisture. Soil moisture is increased by placing 

 a layer of sphagnum moss over the tile or bricks at the 

 bottom of the propagating bench. The moss has a pecu- 

 liar cell structure which permits it to absorb large quanti- 

 ties of moisture, and to hold it in reservoir-like cells. It 

 should not, however, be thick enough to prevent free 

 drainage from the medium in which cuttings are placed. 

 Careful attention should be given the watering of the cut- 

 ting bench. At no time should it be allowed to become 

 dry or even partially dry. 



Atmospheric temperature. Atmospheric temperature 

 is controlled principally by ventilation and by the shading 

 of glass. As a rule, the atmospheric temperature should 

 be ten degrees lower than the soil temperature about the 

 cuttings. All drafts over the cutting bench should be 

 prevented, for they not only check uniform growth in cut- 

 tings, but they increase rapidity of transpiration. They 

 may also foster disease. 



Atmospheric moisture. Atmospheric moisture is con- 

 trolled by having a low roof over the cutting bench and by 

 frequent dampening of the walks and the area underneath 

 the benches. Careful attention should also be paid to 

 ventiliation, which has a marked effect on atmospheric 

 moisture. Too moist an atmosphere, however, favors the 

 development of fungous diseases, especially the " damp- 

 ing off " fungus, and so should be guarded against. 



Light conditions. Ideal light conditions over cutting 

 benches come from a northern exposure. If the bench is 

 so located that it may get the early morning and the late 

 afternoon sunshine, most healthful conditions will be pro- 

 duced. Cuttings, when first made, should always be 



