Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. When you get a container plant from a nursery, usually you see what looks like tiny plastic balls on the top of the soil. The technical name for these structures is a prill and they are examples of a slow-release formulation, polymer coated fertilizer. Different blends of fertilizer, mostly nitrogen, phosphorus and potassiuim but sometimes with micro-nutrients as well, are coated with varying thicknesses or a protective material that slowly with exposure to water, temperature and other factors, degrades and releases the fertilizer into the soil. The thicker the coating, the longer the fertilizer lasts.
Old-fashioned, quick-release formulations of fertilizer, although cheap, don’t last long and unless reapplied frequently may leave your plants with inadequate levels of nutrients. Slow-release formulations costs more but for most of us saving time and preventing possible off-site pollution make them a good choice.