Abstract: A fertilizer product and method for providing controlled application of high analysis fertilizer. A controlled initial light release of a water soluble plant food consistent with growth requirements of the plant is provided. As the plant increases in size and requires an increase of plant food the subject fertilizer and method supplies increasing amounts of plant food without fertilizer burning. The subject product and method includes a water expandable reverse osmosis membrane barrier, preferably in the form of a collar providing a source of plant food released in controlled varying amounts as required by plant growth.