92 Principles of Plant Culture. 



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 (123) and by proper 

 priming (Chap. IV, Section III). 



If the soil is properly drained, the natural depletion of 

 soil water about midsummer will usually give the needed 

 check to growth. In wet seasons, the drying of the soil 

 may be promoted by stopping cultivation before midsum- 

 mer and sowing a crop that will increase evaporation 

 from the soil, as oats, clover or buckwheat. 



137. Pinching Promotes Flowering (416). In certain 

 cases, as with seedling trees of which we would early 

 know the quality of the fruit, we may give an abnormal 

 check to growth by pinching the tips of the young shoots 

 or by root pruning (416 k). These operations should be 

 performed early in summer, before the period of flower- 

 bud formation, and if the tree is not too young, flowers 

 and fruit may be expected the following season. Frequent 

 transplanting of young trees acts like root pruning, especi- 

 ally if the tap-root is severed. Such harsh measures, 

 however, while they promote early fruiting, doubtless 

 tend to shorten the life of trees. 



138. Ringing (416 g) often Causes the Formation of 

 Flower-Buds in otherwise barren trees, by obstructing the 

 rootward current of prepared food. Twisting a small 

 wire about the branch, violently twisting the branch 

 itself, or simple bending and fastening it in an unnatural 

 position, answers the same purpose. But these devices 

 probably weaken the tree and shorten its life by robbing 

 the roots of their normal food supply and are excusable 



