Comparison of preplant and fertigated micronutrients on the growth of the Hebe ’inspiration’

Abstract

Micronutrients may be provided to plants in containers either via pre‐plant inclusion in the growing medium or via fertigation, or both. For Hebe ’Inspiration’ plants growing in a soilless potting medium, micronutrients applied as a single pre‐plant application or via weekly liquid fertilizer applications were equally effective in producing optimum growth over a 12‐month period. Under the conditions of this experiment, the liquid fertilizer did not need to contain more than (in mg/L) 0.5 = iron (Fe), 0.1 = copper (Cu), 0.1 = zinc (Zn), 0.8 = manganese (Mn), and 0.1 = boron (B). Growth was excellent for the full 12 months, without supplementation via the liquid fertilizer, when there were micronutrient concentrations of (in mg/L extract) 29 = Fe, 0.5 = Cu, 3 = Mn, 0.6 = Zn, and 0.14 = B in a 1:1.5 volume in a 2mM DTPA extract of the medium at potting.