88 Principles of Plant Culture. 
mer,* when a restricted water supply prevents rapid growth, 
but when abundant sunlight and fully expanded foliage 
favor assimilation (59). 
We may infer, therefore, that treatment that favors the ac- 
cumulation of reserve food promotes the formation of flower- 
buds, a proposition that is borne out by the experience of 
practical cultivators. 
136. How can we Promote the Accumulation of Re- 
serve Food? Three general principles may be cited: 
A.—Provide for abundant assimilation by giving sufficient 
light and air and by protecting the foliage from the attacks 
of insects and fungi (Chap. III, Section VI). 
B.—Provide sufficient plant food in the soil to satisfy all 
requirements of assimilation (Chap. ILI, Section Y). 
(.—Provide 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 with- 
holding 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 conditions are less under 
control than with plants under glass, but the principles 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 (23) and by proper pruning 
(Chap. IV, Section III). 7 
* Plants that live over winter and bloom in spring, as the apple, strawberry 
etc., form their flower-buds the preceding summer. 
