Improving Zinc And Copper Delivery For Subirrigated Greenhouse-Grown Pot Chrysanthemums

Moderate levels of zinc (3.50, 1.75 or 0.875 mu mol.L-1 Zn) or copper (0.75, 0.38 or 0.19 mu mol.L-1 Cu), in combination with a complete suite of other essential nutrients, were supplied up to flower bud break only, to two cultivars of subirrigated, potted, pinched chrysanthemums. Market-quality plants were produced with sufficient leaf-zinc or leaf-copper even though the delivery of the respective nutrient could be reduced by 75% compared with an industry standard. These results are interpreted as evidence for improved uptake efficiency with decreasing Zn or Cu delivery. Our modified delivery practice could contribute to low-input production of floricultural crops.