PREPARATION OF SOIL 233 



level culture may be practiced, if the soil is in good tilth. The 

 ridge method of culture is suitable to land having a very heavy 

 subsoil, or otherwise not well drained; it is more expensive than 

 level culture. In the level method of planting the rows are two 

 to two and one-half feet apart, and the plants about the same dis- 

 tance apart in the rows, and they may be set in rows both ways 

 to allow of cultivation in both directions while the plants are 



FIG. 167 Fia. 168 







FIG. 167.^-Sweet potato plants when pulled from the bed will vary greatly in size and vigor. 



The best should be selected for setting in the field. (New Jersey Station.) 

 FIG. 168. Short stems and many leaves, as shown at the right, are the result of keeping 

 the plants pulled from the seed bed as fast as they develop. The small plant at left is not 

 desirable. (New Jersey Station.) 



small. If the ridge method is to be used two or more furrows are 

 thrown together with a turning plow, forming ridges about four 

 feet apart. After the ridges settle the plants may be set. If only 

 slight ridges are desired the work of the plow is followed by the 

 harrow before the plants are set. The harrow will reduce the height 

 of the ridges. Slight ridging or level culture is best for dry sea- 

 sons. When the plants are set in the ridges a distance of about 

 eighteen inches is left between plants in each row. 



