Abstract

Water-holding capacity of substrates increased as the proportion of sphagnum peat and coir increased, and coir-based substrates had greater water-holding capacities than comparable peat-based substrates. There were no significant differences between coir and peat-based substrates with respect to bulk density, percent pore space and percent solids. Air-filled pore space and water-filled pore space decreased and increased, respectively, as the proportion of peat and coir increased. ‘Pink Elite’ geranium plants grown in coir-based substrates had greater root fresh weights than those grown in sphagnum-peat based substrates. Greatest root fresh weight occurred in an 80% coir and 20% perlite substrate. Days to flower, height, shoot fresh weight and number of axillary shoots were not significantly different between substrates. ‘Janie Bright Yellow’ marigold and ‘Blue Lace Carpet’ petunia plants had increased heights and shoot fresh weights when grown in coir-based substrates as compared with sphagnum peat-based substrates. Greatest heights and shoot fresh weights of petunia and marigold occurred in an 80% coir and 20% perlite substrate. Days to flower were reduced for marigold plants grown in coir-based substrates.