INFLUENCE OF P FERTILITY ON SWEETPOTATO ROOTING DURING CONTAINERIZED TRANSPLANT PRODUCTION

A market for edible landscape transplants continues to increase for vegetable production in the home landscape. A method for extending the salability of sweetpotato transplants in retail outlets is needed because containerized transplants can develop spiraling roots and deformed storage roots. Implementing traditional techniques to ameliorate container-bound roots before planting in the landscape is not advisable. Altering P fertility is a non-chemical and non-mechanical method for slowing sweetpotato rooting. Therefore, sweetpotato cuttings were planted in 100% sand-filled containers and fertilized at 0, 5, 10, 15, 20, and 31 mg L-1 using a modified Hoagland solution over a 6-week period. Each week transplant shoots were measured for shoot length, quality, and biomass and roots were analyzed for total root length (TRL), root surface area (RSA), root volume (RV), average root diameter (ARD), and biomass. All sweetpotato transplants fertilized at ≥ 5 mg P L-1 increased in plant length, quality, and biomass for the first four weeks after planting (WAP) followed by declines in transplant quality. Rooting followed a similar pattern for all architectural parameters but continued to increase throughout the duration of the experiments with the exception of the control. Reducing P fertility from 15 to 5 mg L-1 slowed root growth, it was not sufficient to extend the salable period beyond 4 WAP. Therefore, sweetpotato transplants ideally would be established in the landscape within 4 WAP to minimize effects from root spiraling and reduce storage root deformation