Growth of Phalaenopsis Plants in Five Different Potting Media

Abstract

To clarify suitable media for the mass production of phalaenopsis orchids, five potting media, New Zealand sphagnum moss (SM, as the control), coir mixes (CM), CM partially mixed with SM, granular rockwool mixes and perlite mixes were examined using clonal plants of two cultivars, ‘Stripe’ and ‘White Red Lip’, at two-month-old and eight-month-old stages. In pots filled with 100% SM, water retention and total porosity were the greatest, while pH and EC were the lowest. In perlite mixes, water retention and total porosity were the lowest. The CM partially mixed with SM yielded significantly greater number of leaves, and fresh and dry weights of both cultivars at the two growth stages. Scanning electron micrographs showed no differences in the shape of stomata or transversal cells of roots among plants in pots with five different media, while leaves of granular rockwool mixes produced abundant wrinkles on their epidermis. The CM partially mixed with SM was a practical potting medium replacing SM, because of its higher potential to support the superior growth of phalaenopsis.