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How To: read fertilizer labels
17 Feb, 2009 By: Fred Hume Athletic Turf NewsThe most important rule to follow is using any chemical products is to always "read the label." In many cases the label is the law. Off-label usage, particularly of pesticides, is illegal and could lead to serious legal liabilities.
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While fertilizer application practices are far less regulated (at least right now), the information on the outside of a bag tells you a great deal about the results you can expect.
Unfortunately, many landscapers don't take time to scrutinize the label and buy the wrong product or misuse it. The information on the label isn't just hype or a tangle of indecipherable statistics; it can help you choose a better fertilizer or improve the efficiency of your current fertilizer.
Depending on its type and brand, there may be a variety of information provided on both the front and back of a fertilizer bag. While the law mandates that some of this information be listed, many companies provide tips and suggestions to optimize your fertilizer program.
A look at the label
The Association of American Plant Food Control Officers (AAPFCO) is a coalition of state and federal officials who work with fertilizer companies to regulate what information by law is required to be on a fertilizer bag's label and the standard format for displaying this information. The AAPFCO is concerned with ensuring companies meet the specified nutrient levels or support any other claims made on the label. It requires each bag of fertilizer to clearly display: brand, grade (N-P2O5-K2O analysis – e.g. 20-10-20), guaranteed analysis of all essential nutrients, name and address of the fertilizer company (registrant) and directions for use.
The Guaranteed Analysis (G.A.) allows you to judge different fertilizers on an apples-to-apples basis. This analysis clearly states what nutrients are being claimed and from which form they are derived. Other key elements of a G.A. include:
- Nitrogen system: the percentage of nitrate N, ammonical N and urea N
- Designation of water soluble or insoluble nutrient sources that tells you how available nutrients might be
- Chelated or other micronutrient sources.
- All of the nutrient raw material components used to make the fertilizer (listed in the "derived from" statement.)
- The percentage of ingredients guaranteed to be slow-release, which is only required for coated or slow-release fertilizer products. This gives you an estimate on what portion of the product will give you sustained feeding of turf and landscapes. It's the basis for any longevity claim on the label.
- A complete label is required even if a product is sold as a custom-blended product. A custom-blend by definition is a formulation made on request specifically for only one customer.
Other claims
Additionally, if fertilizer is combined with pesticide, insecticide or herbicide, the product is then considered a pesticide, insecticide or herbicide, and its label must contain all the required information, precautions and warnings listed on the active ingredients label. On such products, the label is the law, and it is essential that users read the label thoroughly to ensure correct and safe application. Fertilizer regulators may step in when companies claim that a fertilizer possesses non-nutritive benefits, such as fighting disease, promoting health or acting as a growth regulator. If these companies cannot support these claims with credible research, they may be forced to retract their claims and may face fines.
Directions for use
The required information in the "directions for use" statement is subject to less industry standardization. Some labels include almost no information on product usage, while others are quite comprehensive. Here are some of the useful features you might find on the back of fertilizer bags:
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