GRAPE PRUNING AND TRAINING 



299 



this case is that the renewal spur shall be below the fruit cane, that 

 is, nearer the trunk. 



Replacing spurs for shortening the arms are occasionally needed 

 as in spur pruning, but usually the same spur may be used both for 

 renewal and replacing. The water sprouts, c, may be used for this 

 purpose, cutting it at 1 or :i, according to its vigor. 



215. Time to prune vines. The most extensive and im- 

 portant pruning is done during the dormant season. 

 Vigor and fruitfulness are often profoundly influenced by 

 the time the work is done, so are the quantity and the 

 location of the reserve plant food in the vines. J. L. 

 Vidal, a French investigator, has studied minutely the 

 nutrition of the European grapevine.* Among his find- 

 ings the following are of special interest at this point. 

 In summer the leaves feed the various other parts (29) 



at* 

 FIG. 258 -UNIT OF LONG PRUNING OF GRAPEVINE 



Just before the leaves normally drop the canes are richest 

 in plant food. Immediately after the leaves drop and 

 during the following two to five weeks, this food is carried 

 to the roots, where it is held in storage. Part of this as- 

 cends again gradually during the dormant period to 

 supply the needs of the parts above ground ; for even 

 though dormant these parts must be nurtured. When 

 spring opens the ascent of this food is often extremely 



* "Les Reserves de la Vigue." Revue de Viticulture I, Pages 895 to 903. 



