AN EVALUATION OF PERLITE-BASED SUBSTRATES FOR ORNAMENTAL POT PLANT PRODUCTION

Sphagnum peat dominates the horticultural substrates market in Europe. However, environmentalists are increasingly concerned about the use of peat in horticulture, arguing that harvesting destroys ecologically fragile, wetland habitats. In other parts of the world, reliable supplies of good quality substrates can be difficult to obtain. There is a need, therefore, to assess other materials that might act as peat substitutes.

Preliminary trails were conducted to evaluate the potential of the inert substrate, perlite, for ornamental pot plant production. Micropropagated plants of Ficus elastica 'Robusta' were potted into fine perlite containing one of four base dressings. Liquid feeds, specific to each base dressing, were applied according to need assessed by potting mix nutrient analysis. After 18 weeks, ten objective measurements of plant growth were made, together with a subjective assessment of marketable quality and compared against plants grown in a peat-based mix.

Plants grown in three of the four perlite treatments had a higher marketable quality rating than plants grown in peat.