Great question. The answer is both \"no\" and \"yes\". If you are talking about Osmocote Plant Food, the answer is \"no\". If you are talking about Miracle-Gro Shake 'n Feed or some of the other brands, the answer is probably \"yes\". Turns out, not all slow-release fertilizers are the same. Here's the deal. Osmocote's unique coating releases its nutrients based on the temperature of the soil (not the ambient temperatures reported by the media!). Most other slow-release fertilizers use a coating that is water soluble so the release starts when the granule becomes wet. High humidity probably affects these moisture-activated granules. One more thing to remember about Osmocote, the higher the soil temperature, the faster it releases. Plants feed the same way, that is, they take up more nutrition when the soil is warmer and less when it is cooler. The longevity quoted on a package assumes a constant soil temperature of 70 degrees. When the soil temperature (for Osmocote, anyway) is above that point, the release is faster and the product will not feed for as many months as the package says. For example, an 80 degree soil temperature will shorten Osmocote Outdoor & Indoor from 4 months (at 70 degrees) to 3 months. I'm guessing the soil temperature in Central Florida exceeds 70 degrees in the dead of summer so you should feel comfortable in feeding plants sooner than the package says. Osmocote is formulated with a safety factor that allows the product to be over-applied by a factor of 3 or 4 before damage to the plant will occur. Last point, in case you are wondering why we seem to know so much about Osmocote, that's because it sponsors this site and we have access to its scientists. Thanks, again, for the interesting question! Keep growing! Marianne Binetti.