How to Fertilize Your Lawn

Lawn fertilizers consist of nitrogen, phosphate, potassium and other nutrients. Of these, nitrogen is the most important for healthy growth.

From: National Gardening Association
Fertilizing the Lawn

Fertilizing the Lawn

Photo by: Image courtesy of Ben Rollins.

Image courtesy of Ben Rollins.

Fertilize during the lawn's most active growth periods: spring and fall in cool climates and early and late summer in warm climates. Avoid fertilizing during very hot weather, when many grass lawns are essentially dormant.

Materials Needed

  • lawn fertilizer
  • fertilizer spreader
  • water and lawn
  • sprinkler

Step 1: Determine Grass Type

Different grasses need different amounts of nitrogen per 1,000 square feet of lawn per year. Blue gramma, buffalo, and centipede grasses need up to 2 pounds. Bahia, ryegrass, fine fescue, St. Augustine, and zoysia grasses need 2 to 4 pounds. Bentgrass, Bermuda, Kentucky bluegrass, and tall fescue need 3 to 6 pounds. Use the upper end of the range in warmer climates that have longer growing seasons, and less in cooler climates with shorter growing seasons. Take a soil sample from your lawn to a garden center or testing lab for analysis every three to four years to find out the correct amount of nutrients and other additives, such as lime, sulfur, or gypsum, your lawn needs.

Step 2: Calculate Nitrogen on Bag

The numbers on the bag, such as 25-5-5, refer to the percentages of N-P-K in the fertilizer. To calculate the actual pounds of N-P-K a fertilizer contains, multiply the percentage (number) times the weight of the bag. A 50-pound bag of 25-5-5, for example, contains 12-1/2 pounds of nitrogen (.25 x 50).

Step 3: Calibrate Spreader

Adjust the setting on your spreader to the number recommended on the fertilizer bag. If the calibration setting is not given, calculate it using the following method: weigh the correct amount of fertilizer needed for 100 sq. ft. Using the spreader, apply the measured amount on a 100 sq. ft., hard, clean surface. Adjust the setting as necessary. Sweep up and return fertilizer to the spreader.

Step 4: Spread Fertilizer

Spread fertilizer around the perimeter of the lawn or section of lawn first. Then move back and forth in slightly overlapping strips to cover the whole lawn evenly with fertilizer.

Step 5: Water Lawn

A day or two before applying the fertilizer, water the lawn thoroughly. Apply fertilizer once the grass is dry, then lightly water again to wash the fertilizer off the grass blades and into the soil.

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