Lots of good questions. Thanks for asking. The best soil temperature for plants in much of North America is between 45 and 75 degrees with the sweet spot being between 55 and 65 degrees. Remember, we're talking soil temps, not air temps. Soil temperature matters because plants feed through their root systems. Root systems stressed by cold are less efficient at taking up nutrients. That's why you've heard that plants need a higher dose of nitrogen in cold weather. In colder soil conditions Nitrate Nitrogen works best. Osmocote Outdoor & Indoor Plant Food contains 19% Nitrogen (9.8% in the form of Nitrate Nitrogen). The unique, polymer coating on each Osmocote granule governs the nutritional release. Because it works through the principle of osmosis, it replaces the nutrition that is taken-up by the plants root system on a 1-to-1 basis. Plants get exactly what they need, and when they need it. The best way to apply Osmocote is to sprinkle it onto the soil and then mix it into the top 1 - 3 inches. The bottle says to use 1 capful per 4 sq. ft. Personally, I pour a handful and slowly shake my hand while it dribbles out between my fingers. I tend to be a bit generous with my handfuls (more is always better, right?). Even if you over apply to the soil it won't damage the plant because the release is governed by the principle of osmosis. The company says it is safe to over apply up to a factor of 3X but I've talked to PhD scientists who say privately that it won't burn up to a factor of 6X. Keep growing, Marianne Binetti