The Use of Coir as a Containerized Growing Medium for Douglas-fir Seedlings

Abstract

In response to environmental concerns and the need for peatland conservation, alternative growing media for conifer seedling production must be investigated. We grew Douglas-fir seedlings in 6 media; components included peat moss, peat moss amended with sawdust, and 2 sources of coir (coconut fiber) mixed with and without peat moss. Coir had higher pH, P, K, and Na and lower Ca and N than peat moss and a peat moss-sawdust mixture. Bulk densities of coir and coir-based media were lower than those in peat moss and a peat moss-sawdust mixture. After 21 wk, seedlings grown in coir-based media were significantly smaller and had lower foliar N and Ca than those grown in peat moss. Because of coir’s many favorable qualities, we suggest further research using culturing regimes specific to the substrate’s nutrient properties.