HLTLLETIN 197. GRAPE CULTURE IN CALIFORNIA. 123 



Most of the cases of failure have been reported from Sonoma, Napa, 

 and Santa Clara counties. They can nearly all be traced to unsuitable 

 soil conditions. "Where there is an impermeable subsoil (bed rock or 

 compact clay) the St. George usually fails. Under such conditions, if 

 the soil is dry, the vines make poor growth; if wet, the roots decay 

 and the vines die. A very compact clay soil, even when deep, seems 

 unsuited to this variety, at least when grafted with certain varieties, 

 such as Emperor and Cornichon. 



In some cases the vines grow well, but the crops are unsatisfactory. 

 This has been noted only in rich valley soil of the coast counties and 

 only with certain varieties. A similar condition has often been noted 

 in Europe, but it is usually easily overcome by longer pruning and 

 diminishes with age. 



A more serious defect has been found in some of the cooler districts. 

 Many varieties when grafted on St. George ripen from one to two 

 weeks later than when grafted on Kip aria and some other stocks. This 

 is due, probably, to the great vigor of the stock, which keeps the vine 

 growing late. It is a serious defect wherever there is difficulty in 

 obtaining the desired amount of sugar in the grapes and wherever 

 late grapes are liable to injury from the autumn rains. 



It seems inadvisable, therefore, to plant St. George in cool situations, 

 on northerly slopes of the coast ranges, in localities close to the coast, 

 or on shallow, wet, very rich or stiff clay soils in any locality, and to 

 use it only on deep, permeable soils in the warmer districts and 

 locations. 



EXPERIMENTS WITH VARIOUS STOCKS. 



Through the courtesy of Mr. J. K. Moffit we have been able to take 

 some very interesting notes on resistant vines at an experiment plot in 

 his vineyard at St. Helena, Napa County. 



This plot was planted in 1900, under the direction of the Experiment 

 Station, with the resistant stocks and bench grafts which served for 

 the experiments detailed in Bulletin 127. Since that time it has been 

 looked after by Mr. B. Bruck, the manager of the vineyard. The fol- 

 lowing is a summary of the notes taken in 1905. 



Three rows of 25 vines each were planted with various varieties of 

 bench grafts; in one row the stock being Rupestris St. George, in 

 another Riparia Gloire, and in the third Riparia Grande Glabre. In 

 most cases there were two vines of each variety on the same stock, in 

 some cases three, and in some only one. The results are, therefore, not 

 quite so convincing as if they had been made on a larger scale: 



