PROPAGATION BY BUDS LAYERAGE 85 



to open ground; b, by "sprouting" that is, planting sets thickly in 

 cold frames, and when ready to "break ground" transplanting them 

 to the field, etc.; c, by "budding" that is, subjecting seed tubers the 

 size of hens' eggs from four to six or more weeks to the action of 

 moderate heat and light so one or two strong buds of a dark color 

 and ready to develop leaves and roots are formed on each tuber, 

 while all other buds remain practically dormant. Budded seed 

 tubers, compared with dormant ones, in 89 days from planting gave 

 an increase of nearly 22 bushels of merchantable potatoes and a gain 

 in total yield of 32 1-3 bushels an acre. Compared in 111 days they 

 gave an increase of 41 bushels of merchantable potatoes and a total 

 gain in yield of 54 2-3 bushels an acre. For budding, seed tubers of 

 one to three ounces are to be preferred. They may be "greened" by 

 exposure to light on ground free from vegetation, directly after 

 digging, and placed in trays at any convenient time during winter. 



130. Germinating seed potatoes in boxes in Scotland has given an 

 average of nearly 1,100 pounds an acre gain in crop. Potato tubers 

 partially dried are also said to make more productive *plants than 

 those not dried. 



131. Sweet potato propagation Sweet potatoes develop new 

 stems from adventitious buds which appear anywhere on the surface. 

 Usually they are propagated by being split lengthwise in early spring 

 and laid flat side downward in a mild hotbed filled with light soil 

 or sand. The "slips" or sprouts are carefully pulled when four to 

 six inches long and transplanted in the field. New varieties of Irish 

 potato are often propagated in this way and also by stem cuttings 

 so produced (166). 



