Numbers of fleshy root and patterns of weight gain for commercial root grades of four sweet potato cultivars are reported for 11 harvest dates starting 50 days after transplanting (DAT) and ending 120 DAT. Significant harvest data differences were found for all variables measured. Cultivars differed significantly for all variables except number and fresh weight of medium-size roots. Percentage dry weight differed at four locations during growth and development. Numbers of small-size roots measured 50 DAT, rate of weight gain for large-size fleshy roots, and the percentage dry weight of shoot tips measured 71-120 DAT were found to influence final root yield.