Optimizing Boron and Molybdenum Delivery for Contrasting Cultivars of Subirrigated, Greenhouse-grown Pot Chrysanthemums

Greenhouse floriculture operations must produce high‐yielding, quality flowers while minimizing environmental risk. I hypothesized that boron and molybdenum delivery to modern cultivars of subirrigated chrysanthemum can be optimized, compared to industry standards, while maintaining plant yield and quality. Two experiments were conducted for each micronutrient in a naturally‐lit greenhouse using a randomized complete block split‐plot design. Boron (5.00–0.313 μmol L–1) or molybdenum (0.50–0.031 μmol L–1), corresponding to 100–6.25% of current industry standards, was supplied in an otherwise balanced nutrient solution during vegetative growth only. Plant/flower morphology and development, visible symptoms of nutrient deficiency, and tissue nutrient levels indicated that boron and molybdenum supplies could be successfully reduced by 75–94% through improved nutrient use efficiency. This research contributes to the development of a sustainable low‐input nutrient delivery strategy for floricultural operations, wherein nutrient supply is interrupted during reproductive growth and optimized during vegetative growth.