Abstract

Three species of foliage plants were produced with three media, in an ebb and flow irrigation system (experiments 1 and 3) or with overhead manual irrigation (experiments 2 and 4). Expt. 1 used a constant feed program of 24N-3.5P-13K (24-8-16) soluble fertilizer added to the water supply at rates of 0.21, 0.42, 0.63 or 0.84 g/L. In experiments 2, 3 and 4, plants were fertilized with a constant feed program using the soluble fertilizer at 0.63 g/L or with a 19N-2.6P-10K (19-6-12) slow release fertilizer at rates of 2.5, 5.0 or 7.5 g/15 cm (6 in) pot. Plants produced in a Canadian sphagnum peat:pine bark mix were shorter and received lower plant grades compared to Fafard #4 and Vergro Container Mix. Height increase and plant grade for all plants was greater when fertilizer rate was increased from 0.21 to 0.42 g/L (0.79 to 1.58 g/gal), but height increase and plant grade did not improve much as fertilizer rates rose beyond 0.42 g/L (1.58 g/gal). In expt. 3, increase in height and plant grade for plants treated with 0.63 g/L (2.36 g/gal) soluble fertilizer was similar to height increase and plant grade for plants receiving the 5.0 and 7.5 g/15 cm pot slow release fertilizer.