There are three types or modes of fertilizer granular, liquid and time released. Granular is the least full proof because you can put too much on and harm your plants also granular needs rainfall to break it down. It really needs almost an inch of rain to break it down enough to make it available to the plant. A dose a granular will last thru about three inches of rain or about a month. Liquid fertilizer or water soluble fertilizer is available immediately for the plant but it only lasts about a week. Time released fertilizer will only release fertilizer when it senses that the soil needs it. All fertilizers come labeled with three numbers like 10-10-10. That first number is the percent that is nitrogen. Nitrogen mainly helps out with the top growth of the plant. This is the most misused of all your fertilizer - nitrogen. It will give your plant a surge growth and what it can do if it's put on too early is to cause your beans to grow a massive bean vine and it works the root structure to death trying to feed all that vine. And it then cuts your crop. Most vegetables doesn't need nitrogen until it gets close to starting to produce it's crop. Beans need nitrogen when they start blooming. So watch out for fertilizers with that first number that's over 5 or 10 unless you are at the stage that the plant is about ready to produce. The second number is the percent of phosphorus that promotes bloom and root growth, especially blooms. So if you have a plant that is producing off it's blooms like tomatoes or cucumbers. Then look for a high middle number on your fertilizer. The third number is pot ash that mainly promotes root growth. So things like carrots and potatoes benefit from a fertilizer with a high third number. So don't use the same ratio or fertilizer for all your plants in your garden thru the hole year. Think about what you are trying to produce and at what stage your specific plant is and what component or number it needs at that point. Going to a local farm supply store and getting your granular nitrogen, phosphorus and pot ash separately will allow you to create your own ratio of numbers or your own fertilizer mix for your different types of plants. Finally remember you can loose nitrogen thru evaporation. So keep your fertilizer mix in a sealed container and make sure to cover it with dirt when you do put it on.