Calculate exactly how much fertilizer to apply based on your lawn size and desired nitrogen rate.
Fertilizer bags list an N-P-K ratio (like 20-5-10), where the first number is the nitrogen percentage. Lawns are typically fed at a target rate of nitrogen per 1,000 square feet.
Fertilizer Needed (lb) = ((Lawn Area ÷ 1000) × Nitrogen Rate) ÷ (Product Nitrogen % ÷ 100)
A 5,000 sq ft lawn at 1 lb nitrogen per 1,000 sq ft needs 5 lb of nitrogen total, which is 25 lb of a 20% nitrogen product.
It's based on lawn square footage and the fertilizer's nitrogen content, targeting a specific pounds-per-1,000-sq-ft rate.
It shows the percentage by weight of Nitrogen, Phosphorus, and Potassium in that order.
Excess fertilizer can burn grass and contribute to nutrient runoff into waterways.