Answer: The first number represents nitrogen (N). Nitrogen is the "leaf maker", it is responsible for green, vegetative growth. The second number represents phosphates (P). It is primarily involved in strong, healthy root development. The last number represents potash (K), it is mainly responsible for making flowers. Based on that, you would want high numbers of each depending on what you want to grow. For example...growing spinach? Go higher in the nitrogen. Growing roses? Go easy on the nitrogen(or you will have a lot of green foliage but no flowers) and harder on the phosphate and potash.
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