Question: Which is better, 21-7-14 or 15-5-10? I see both at the nursery.

Answer: Both are 3-1-2 ratio fertilizers. Check the fine print to see how much of the nitrogen (first number of the analysis) is in a slow-release encapsulated form. If those percentages are equal you should expect to pay approximately 50 percent more for the 21-7-14 than you do for the 15-5-10, simply because it has that much more nutrient content. If the prices don’t follow that pattern, select the one that is the better value.