2018 ASHS Annual Conference
Limiting Phosphorus and Potassium Controls Plant Growth of Floriculture Species
Limiting Phosphorus and Potassium Controls Plant Growth of Floriculture Species
Tuesday, July 31, 2018: 3:30 PM
Georgetown West (Washington Hilton)
Four floriculture crop species [‘Magellan Cherry’ zinnia (Zinnia elegans Jacq.), ‘Festival Golden Yellow with Eye’ gerbera (Gerbera jamesonii Bolus ex Hook. F.), ‘Pacino Gold’ sunflower (Helianthus annuus L.), and ‘Accent Salmon Premium’ impatiens (Impatiens walleriana Hook. F.)] were grown under fertilizer treatments of varying concentrations of phosphorus (P) (20, 10, 5, and 0 mg·L-1 P) and potassium (K) (150, 112.5, 75, 37.5, and 0 mg·L-1 K). For marketable plants that exhibited limited nutritional disorder symptoms, limiting P controlled height of impatiens and diameter of gerbera, impatiens, sunflower, and zinnia, and lower concentrations of K limited the height of gerbera inflorescence and the diameter of impatiens. Reducing P resulted in fewer lower yellow leaves during postharvest on gerbera, sunflower, and zinnia. However, low concentrations of K resulted in higher numbers of yellow leaves during postharvest conditions for impatiens, sunflower, and zinnia. Our results suggest that growers can limit P and K to levels of 5 mg·L-1 P and 37.5 mg·L-1 K, respectively, to potentially control growth on floriculture crops with limited impact on quality during production.