From Seed to Seed:
Plant Science for K-8 Educators

Digging Deeper

5-5-5???

All-purpose fertilizers contain balanced amounts of the three major nutrients, nitrogen (N), phosphorus (P), and potassium (K). Packages of synthetic fertilizer include labels with numbering systems such as 5-5-5, 5-10-5, 10-10-10. These formulas represent the ratio of N:P:K in the fertilizer. Different ratios are desirable for different types of plants. For example, flowering plants, bulbs, fruits, root crops, and vegetables require more phosphorus than potassium and nitrogen. For these crops, gardeners may choose a 8-12-4 formula.

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