June 26, 2008

LANSING - As summer approaches, the Michigan Department of Agriculture (MDA) reminds homeowners they can prevent excess applications and cut costs by reading fertilizer labels carefully when treating their lawns. A fertilizer label provides important information about plant nutrients, application recommendations, and expected results.

“Applying too much of any nutrient can become harmful to the plant and the environment, so follow label recommendations closely,” said Ken Rauscher, director, MDA Pesticide and Plant Pest Management Division. “When in doubt, use less and not more.”

To ensure you don’t over apply fertilizer, carefully read the directions for use on the label. Directions for use provide application recommendations and list spreader settings designed to apply the desired amount.

On any fertilizer bag or box, there is a series of three numbers or “grade,” such as 12-2-4. These numbers state the percentage by weight of the three major nutrients plants need in order of importance: nitrogen, phosphorus, and potassium. For example, a bag of fertilizer labeled 20-2-10 contains 20 percent nitrogen, two percent phosphorus, and 10 percent potassium. The other 68 percent is usually inert filler material, like limestone or clay. The purpose of the inert material is to help distribute the nutrients evenly and prevent chemical burn.

Nitrogen, phosphorus and potassium provide the following benefits:

• Nitrogen is essential for plant growth and gives lawns their vivid green color.
• Phosphorus is important for root growth and the establishment of new seedlings.
• Potassium is necessary for root development and disease resistance.

“Soil testing is an efficient way to determine what type of fertilizer is needed,” said Rauscher. “By analyzing for the pH and available plant nutrients in the soil, consumers avoid excess fertilizer applications and maintain a healthy lawn.”

Through its inspections of fertilizer, feed, seed, liming materials, and animal remedy products, MDA helps ensure that agricultural products and commodities are properly labeled, marketed fairly and are safe for their intended uses.

To learn more about MDA’s fertilizer program, visit www.michigan.gov/mda-fertilizer. For more information about Michigan State University’s Soil and Plant Nutrient Laboratory, visit www.css.msu.edu/SoilTesting.cfm.