A set of short-term experiments on the establishment of sweet potato stem cuttings was conducted under greenhouse conditions and terminated at about 30 days after transplanting. The following recommendations can be made. When drought stressed, a stem length of 30 cm (versus 15, 20 and 25 cm) with 10–15 cm of the stem covered by soil produced the most vigorous growth, an important asset when early season weed competition is evident and when rapid ground cover is important. The advantages of dipping cuttings into a dissolved root hormone were cultivar dependent, but pre-rooted cuttings were of no benefit to either cultivar in terms of survival and growth. During establishment, drought significantly reduced the stem weight and leaf weight and area, and similar but non-significant trends were also evident for root number and weight.
Holwerda, H. T., & Ekanayake, I. J. (1991). Establishment of sweet potato stem cuttings as influenced by size, depth of planting, water stress, hormones and herbicide residues for two genotypes. Scientia Horticulturae, 48(3-4), 193-203. https://doi.org/10.1016/0304-4238(91)90127-K