4 THE BOOK OF THE GREENHOUSE 



draught. In comparison with the top ventilators, those 

 at the sides or bottom of the house are quite unimpor- 

 tant ; indeed, many of the best plant growers of the 

 present day never use side ventilation at any time, 

 reckoning it not only useless but harmful for many 

 plants, as it dissipates too readily the natural humidity 

 created in a houseful of plants, and which the great 

 majority of plants enjoy. Some plants, however, 

 prefer a dry atmosphere, and for these side ventilation 

 should be arranged and used cautiously : a few small 

 sliding shutters placed low down, so that the fresh air 

 may feel the influence of the hot water pipes in cold 

 weather, will suit the requirements admirably. 



We will now consider the question of the stages or 

 benches to be used. This is not the unimportant matter 

 that it is often considered to be. I attribute many of the 

 failures and the successes largely to the staging arrange- 

 ments of the house. The most common method of stag- 

 ing plants is to put them on benches formed of narrow 

 strips of wood placed an inch or two apart, thus 

 having an open space between them. This I consider 

 to be quite the worst form of staging, and more especi- 

 ally so where the hot water pipes are placed immediately 

 beneath such stages, for the fire heat necessary in very 

 cold weather does much harm to the root action by over 

 drying the pots, and thus killing the tips of tender root- 

 lets. Undoubtedly the best of stages are formed by 

 good thick slates, as these are always cool and slightly 

 absorbent, so that the bottoms of pots standing on them 

 never become really dry ; but slates are expensive to 

 begin with, and wood does nearly as well provided that 

 the boards are placed close enough together to support 

 a surfacing of shingle, ashes, or some other covering 

 of an absorbent nature. A narrow strip can be nailed 

 round these wood benches to retain the inch or so of 

 this material. All stages placed over hot water pipes 



