a multiple effect plant growth promoting mixture is provided that includes a first plurality of fertilizer granules , each containing a quantity of a bioavailable source of nitrogen , phosphorus , or potassium . a second plurality of granules , each containing an active agent effective in inhibiting an organism interfering with plant growth are intermixed with the fertilizer granules . the fertilizer granules are substantially devoid of the active agent adhering to the fertilizer granule and the active agent granules are substantially devoid of fertilizer . the potential for cross contamination being associated with granule breakage associated with intermixing and transport .