Propagation 77 



Care of the plant-bed. 



When the plant-bed has been placed in an ideal loca- 

 tion, the bottom-heat perfectly regulated, the top soil or 

 sand carefully selected and applied for its purity and 

 freedom from disease, and the tubers which have been 

 carefully selected and treated for disease are evenly 

 placed in the bed and covered, the task of producing 

 strong vigorous plants which will vitally influence the 

 crop yield is only half accomplished. A sweet potato 

 plant-bed may be perfectly prepared but unless properly 

 cared for discouraging results will be the' consequence. 



Maintaining temperature. — As has been stated, the 

 temperature of the plant-bed should be between 80 and 

 90 degrees F. or around 85 degrees F. when the tubers 

 are bedded. This heat should be allowed to decrease 

 gradually until a constant uniform temperature of 70 to 

 75 degrees is reached at the end of about six weeks. In 

 no case should the temperature be allowed to go below 

 60 degrees F. as it is sure to cause injury to the growing 

 shoots. The temperature of the bed should be noticed 

 carefully every day for the first ten days. A ther- 

 mometer should be kept continually in the soil. In 

 these first few days a manure-heated bed may suffer 

 considerable variation in temperature which will re- 

 quire regulating. In case the bed is not well drained, 

 excess water may find its way into the manure, destroy- 

 ing the heat altogether or starting a new fermentation 

 resulting in the production of heat too intense for the 

 well-being of the young sprouting buds. In case of 

 extreme heat, enough water should be applied thor- 

 oughly to wet the surface sand. A double row of 3- 

 inch holes, 1 foot apart, should then be worked along 



