A vegetation culture active agent delivery medium is provided that
includes dense mineral granules, comparatively less dense cellulosic
granules, and an active agent in simultaneous contact with the mineral
granules and the cellulosic granules, the active agent present from
1.times.10.sup.-5 to 10 total weight percent of the medium. A formulation
of an active agent is applied to one type of granule as a mixture
thereof. Through control of the relative amounts of mineral and
cellulosic granules, a controlled medium density is readily adjusted
between 35 and 60 pounds per cubic foot.