58 MANUAL OF AMERICAN GRAPE-GROWING 



"About the middle of March the temperature of the bed 

 should be raised. This is done by removing the cover during 

 warm days and carefully covering at night. If necessary the 

 layer of moss or straw should be removed on sunny days and 

 then replaced. The temperature of the sand at the level of 

 the unions should be about 75° F. during this period. If the 

 temperature rises higher than this, there will be a more abun- 

 dant production of callus, but it will be soft, easily injured, 

 and liable to decay. 



"At the end of four weeks after warming the bed, the union 

 should be well cemented. The callus should not only have 

 formed copiousl}^ around the whole circumference of the wound, 

 but it should have acquired a certain amount of toughness due 

 to the formation of fibrous tissue. It should require a pull 

 of several pounds to break the callus and separate stock and 

 scion. When the callus has acquired this quality the grafts 

 are in condition to be planted in the nursery, and ma}' be 

 handled without danger. If taken from the bed while the 

 callus is still soft, many unions will be injured and the grafts 

 will fail, or unite only on one side. 



"If left as long as this in the callusing bed most of the scion 

 buds will have started and formed white shoots. These 

 shoots, however, should not be more than i to 1 inch long. 

 If they arc longer the bed has been kept too wet or too warm. 

 Roots will also have started from the stock, but these also 

 should not be over i inch long. The grafts should be handled 

 as carefully as is practicable, but there is no objection to break- 

 ing ofY any scion shoots or stock roots which have grown too 

 long. It is almost impossible to save them, and new ones 

 will start after the grafts are planted, and make a perfectly 

 satisfactory growth." 



Care in the nursery. 



The grafts are planted in the nursery, and are given much 

 the same care recommended for cuttings. They may be set 



