366 GLASS STRUCTURES AND GREENHOUSE CROPS 



cotton waste are also used for this purpose, although they 

 are less satisfactory. 



Watering. -- Plants growing under glass need careful 

 watering. During bright sunny weather, when the plants 

 are growing very rapidly, they need much water. Dur- 

 ing bright weather, most crops have to be watered daily, 

 while during cloudy weather, they may not need water 



Fig. 191. Watering the plants in a hotbed. 



for a week. As most fungous diseases of vegetables thrive 

 under warm, moist conditions, all greenhouse crops should 

 be watered early in the morning on bright days, that the 

 foliage of the plants may dry before night. The soil 

 should be thoroughly moistened as deep as the roots 

 extend. Watering in the evening not only increases fun- 

 gous growth but also tends to chill the bed and thus in- 

 crease the danger of frost. 



