How to Determine the Amount of Phosphorus for Grass

Phosphorus has become a dirty word among the environmentally conscious. Although it's a nutrient that all life requires, excess phosphorus -- that which runs off our lawns and into the waterways -- wreaks havoc with the flora and upsets the balance of nature. Healthy turfgrass blades contain a 0.3 percent phosphorus concentration, according to scientists with the State Environmental Resource Center. Before applying fertilizer to the lawn, take the time to determine how much phosphorus it truly needs. Phosphorus is represented by the middle number on the fertilizer bag.

Things You'll Need

• Knife
• Garden trowel
• Bucket

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Instructions

1. • 1

     Scrape the grass off a small patch of lawn. Use a garden trowel to dig down 3 inches and remove some soil. Repeat this procedure in five random areas around the lawn.

   • 2

     Mix the soil samples in a bucket. The cooperative extension office will advise you as to how much of this combined sample to send. Some offices provide bags or boxes for mailing the samples.

   • 3

     Wait for the soil test results from the extension. The results will let you know how much phosphorus to apply to the lawn.