Lawn fertilizer is dosed by nitrogen, not by the weight of the bag. Getting this right avoids both weak growth and burn.
The N-P-K numbers
The three numbers on the bag are the percentages of nitrogen, phosphorus and potassium. The first, nitrogen, is what drives leaf growth and sets your rate.
Setting a rate
A common target is about 1 pound of actual nitrogen per 1000 square feet per feeding. To find the product needed, divide that nitrogen rate by the nitrogen fraction. A 20 percent nitrogen product needs 5 pounds of product to deliver 1 pound of nitrogen.
Do not exceed the label
More is not better. Over application burns the lawn and runs off into waterways. Follow the label rate and spread evenly.
Work out your rate. Fertilizer Calculator →
Common questions
How much fertilizer per 1000 square feet?
To apply 1 pound of nitrogen with a 20 percent nitrogen product, use 5 pounds of product per 1000 square feet.
What do the N-P-K numbers mean?
The percentages of nitrogen, phosphorus and potassium. Nitrogen, the first number, sets your rate.
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