GROWTH OF BEDDING PLANTS IN MINERAL WOOL AND MINERAL WOOL/PEAT MIXES

Abstract

The objective of this research was to develop a mineral wool based growing medium for the horticultural industry. Two types of hydrophilic mineral wool, clean wool (CW) and unclean wool (UC) were used unamended, as well as both types in combinations with 25, 50, and 75 percent peat moss (PM). A control of 100 percent (PM) was also used. Unamended CW had a low bulk density, excellent water holding capacity, good aeration, but high pH. Once PM was added to CW, bulk density still remained low, water holding capacity and aeration remained good, and the pH dropped to a more suitable level. Unamended UW had a high bulk density, good water holding capacity, poor aeration, and high pH. Once PM was added to UW, bulk density decreased, water holding capacity remained good, aeration increased, and pH decreased to a more optimal level. Impatiens `Violet' and Begonia `Whiskey' were grown in the nine treatments for six and nine weeks respectively. At harvest, plant growth was evaluated by height, diameter, fresh weight, dry weight, and tissue analysis. Plant growth response showed plants grown in unamended CW, UW, and PM were smaller in size and lighter in fresh and dry weights than those in 50 percent wool/50 percent PM. The plants grown in 25 and 75 percent PM were similar to the 50 percent wool/50 percent PM in size and weight.