It is susceptible to soil insects and nematodes. It is best to base fertilizer applications on the results of a soil test . Water in the morning so that the leaves dry before dark. Water sufficiently to moisten the soil to a depth of at least 6 inches. Sweet potatoes need at least 1 inch of rain or irrigation water per week for normal growth.
Water is especially vital during transplant establishment and root development.
Rainfall or irrigation after a long dry period may result in cracking of the sweet potatoes. Cultivate shallowly to prevent root damage. Diseases and insects are, usually, not a problem in the home garden. Wireworm and root-knot nematodes may be a problem. Rotation with corn may help to reduce a root-knot nematode problem, as will the use of resistant varieties.