270 . THE PRINCIPLES OF FLORICULTURE 



requirements vary with the variety grown. As a rule, 

 single varieties flower best in a temperature of from 45 to 

 50 with a day temperature of from 60 to 65. Double 

 violets should be kept cooler, or at a temperature of about 

 40 to 45 at night. It should be remembered that the 

 violet is a crop which demands a low temperature, and that 

 high temperatures will produce an overgrowth of leaves 

 and inferior flowers. 



352. Ventilation and watering. In order to secure the 

 best results, violets should have an abundance of fresh 

 air, but never be chilled, also an abundance of water, 

 for it requires good judgment to keep the soil in the 

 proper condition. The soil should be moist at all times, 

 but there should never be enough water so that it will 

 remain saturated for any length of time. 



353. House culture. Some growers never plant 

 violets in the field. As soon as the plants are well estab- 

 lished in flats, they are placed in coldframes out of doors. 

 The advantage claimed is that the plants receive no check 

 from transplanting in the fall. By the middle of May 

 they are planted in permanent beds in greenhouses, which 

 should have abundant ventilation and be heavily shaded 

 during the summer months. If grown in portable sash 

 houses, the sash is removed after the plants have become 

 well established, and is left off until quite late in the fall. 

 The plants are then cultivated throughout the winter 

 the same as if they were grown out of doors during the 

 summer. 



354. Frame culture with artificial heat. Violets may 

 be grown in frames out of doors if provision can be made 

 for ventilation. This is extremely difficult, however, 

 during cold weather. A deep frame may be built along 

 the south side of a dwelling house, and heating pipes 



