Final answer:
The statement that a fertilizer with zero as the middle NPK number (e.g., 15-0-15) is guaranteed to be phosphorus free under Michigan law is false, as trace amounts could still be present.
Step-by-step explanation:
True or False: If a fertilizer has an analysis with zero as the middle number, for example, 15-0-15, then under Michigan law, the product is guaranteed to be phosphorus free. The answer to this is false. While an NPK rating with a zero in the middle does indicate that there is no added phosphorous in the form of P2O5, it does not necessarily mean the product is completely phosphorus free. Trace amounts of phosphorus may still be present in the product due to the nature of the ingredients used. It is important to read fertilizer labels carefully and refer to specific state regulations for guarantees on nutrient contents.