LEAVES, BUDS AND FLOWERS 85 



buds the preceding season), when a restricted water 

 supply prevents rapid growth, but when abundant sun- 

 light and fully-expanded foliage favor food formation 

 (59). 



We may infer, therefore, that treatment that favors the 

 accumulation of reserve food promotes the formation of 

 flower-buds, a proposition that is borne out by the ex- 

 perience of practical cultivators. 



135. Promoting accumulation of plant-food. Three 

 general principles may be cited for promoting the ac- 

 cumulation of reserve food : 



Provide for abundant food formation by giving sufficient 

 light and air and by protecting the foliage from attacks 

 of insects and fungi ; provide sufficient plant-food in the 

 soil to satisfy all requirements of food formation; pro- 

 vide for a moderate check to growth after the proper 

 amount of growth has been secured. 



In the greenhouse where conditions are under control, 

 these principles are readily followed, and the skilled 

 florist rarely fails to secure bloom at the proper time. 

 He gives the desired check to growth by permitting the 

 roots to become densely matted in the pot (pot-bound), 

 by withholding water, or by pinching the tips of the 

 more vigorous shoots. With out-door perennial plants, 

 as fruit trees, the problem is more difficult, since condi- 

 tions are less under control than with plants under glass, 

 but the principle just cited should always be kept in 

 mind and carried out so far as possible. 



We can give sufficient light and air by planting the 

 trees a sufficient distance apart (122) and by proper 

 pruning (Chap. IV). 



If the soil is properly drained, the natural depletion 

 of soil water about midsummer will usually give the 



