CHRYSANTHEMUM AND POINSETTIA GASIFICATION SLAG AMENDED MEDIA

Coal gasification slag is a by-product of the power industry that may prove useful to the horticultural industry as a component of growing m edia. The objectives of this research are to determine if suitable cro ps of chrysanthemum and poinsettia can be produced in media of slag al one or in combination with moss peat. Chrysanthemums and poinsettias w ere grown in slag or slag mixes in an ebb and flow irrigation system w ith a complete nutrient solution being recycled. Slag alone had a high bulk density and high pH, but adding 50% by volume peat decreased bul k density and pH so that an acceptable growing mix resulted. Weight of plant shoots grown in slag was lower than for plants that were grown in slag mixes. Weight of plants in slag mixes was similar to the peat- perlite control. Plants grown in slag or slag mixes generally were low in phosphorus (P) and manganese (Mn) and high in boron (B). The slag mixes seem to remove P and Mn from the fertilizer solution while relea sing B and to some extent calcium (Ca) to the fertilizer solution.