Healthy Lawns—Site preparation: Starter fertilizer (2024)

Fertilizers contain three primary nutrients

• Nitrogen (N)
• Phosphorus (P)
• Potassium (K)
  

Labels show the ratios of N-P-K (in order) included in the bag of fertilizer. Since phosphorus is the most important nutrient for root development, it is the highest number in a bag of a starter fertilizer. Once the roots are established, nitrogen becomes the most important nutrient for the growth of the aboveground parts.

When to apply

Apply a starter fertilizer before turf establishment and incorporate it to a depth of 2 to 4 inches (5 to 8 cm). If you had your soil professionally tested, the lab will provide guidance on what to apply.

How much to apply

It is recommended that no more than 1 pound of N and at least 1 pound of P per 1000 sq. ft. be applied to the root zone at the time of planting.

The three numbers on a fertilizer label indicate the percentages of nitrogen, phosphorus, and potassium (in that order) in the formulation. For example in the table above, applying 20 pounds of a 5-10-5 fertilizer would contain 1 pound of nitrogen, 2 pounds of phosphorus, and 1 pound of potassium.