Optimizing the Sandponics System for Sweetpotato Prebasic Seed Production

This research brief presents findings from a two-season experiment conducted at the Tanzania Agricultural Research Institute (TARI), Ukiriguru Centre, to optimize sandponics systems for cost-efficient sweetpotato prebasic seed production. The study tested three pot sizes (16 cm, 21 cm, and 26 cm) and planting densities (3, 5, and 7 plants per pot) across varieties Kabode, NASPOT 13, and Polista. Results showed that the 26 cm pot size planted with three vines produced the highest vine yield—averaging 112 cuttings for Polista and 105 for Kabode. Cost-effectiveness declined with increased density, with PP7 treatments showing 79.3% reduced efficiency compared to 15.2% and 5.5% in PP5 and PP3. The findings demonstrate that moderate planting densities and larger pot sizes improve both vine yield and economic efficiency, offering practical guidance for scaling sandponics-based seed production.