How to fertilize a lawn

Updated September 2026 · Lawn Care AI team

Measure the lawn, weigh the fertilizer and spread it evenly. This guide is for granular lawn fertilizer; a product that also contains weed killer needs its own application and watering instructions.

What you need

Lawn fertilizer, its label, a spreader, tape measure, scale, bucket, broom, gloves and a sprinkler if watering-in is required.

Step by step

1. Measure the grass area. Multiply length by width for each rectangle, add the areas and subtract beds and paving. Record either square feet or square metres and use that unit throughout.
2. Choose the amount before filling the spreader. Use the product’s lawn application rate, checked against guidance for your grass and the season. For example, 3 lb per 1,000 ft² on a 2,000 ft² lawn requires 6 lb total. In metric, 30 g/m² on 200 m² requires 6 kg. These are separate examples, not equivalent rates.
3. Check how much nitrogen that supplies. The first number in N-P-K is the nitrogen percentage. Multiply product weight by that number divided by 100. If a plan calls for 0.5 lb nitrogen per 1,000 ft², a 20% nitrogen fertilizer needs 2.5 lb product per 1,000 ft². Do not increase the label rate to reach a generic nitrogen target.
4. Prepare the lawn and spreader. Mow at your normal height beforehand if needed. Apply to dry blades over moist soil, with no downpour expected. Close the hopper and fill over a surface where spills can be collected.
5. Calibrate for two passes. Use the manufacturer’s starting setting, then weigh how much leaves the hopper over a measured test area. Adjust until one pass delivers half your chosen total rate. Half the dial number does not mean half the dose. Count fertilizer used on a lawn test strip toward that area’s total.
6. Spread the measured amount. Cover the lawn once in parallel lanes and once across them, both at the calibrated half rate. Follow your spreader’s recommended lane spacing. Close the gate before stopping or turning. Include edges in the two passes; do not give them extra full-rate laps.
7. Sweep up and water as directed. Collect spills; sweep scattered granules off paving onto the intended treatment area without creating piles. Follow the bag’s watering-in amount and timing. Ordinary granular feeds often need about ¼–½ inch (6–13 mm), but weed-and-feed instructions can differ.

After the job

Keep people and pets off for the interval on the product. Record the date, product and amount. Empty and clean the spreader according to its manual.

Allow the stated response time before judging the result. Do not add a second dose because a slow-release product has not greened the lawn in a few days. Count this application toward the year’s nitrogen total.

Choose a rate for your grass

There is no single fertilizer dose for all lawns. Fine fescues generally need only 0.5–2 lb nitrogen per 1,000 ft² per year (about 2.4–9.8 g/m²), often less in shade. Other species have different needs. Use your grass’s feeding calendar and a soil test for phosphorus, potassium and lime decisions. Newly seeded turf may need a starter application; count it before adding more fertilizer.

Video example

Common questions

Sources and further guidance

• Purdue University — Fertilizing Established Cool-Season Lawns (AY-22-W)
• Penn State Extension — Calibrating Your Fertilizer Spreader
• Clemson HGIC — Calibrating Spreaders
• Clemson HGIC — Fertilizing Lawns
• Minnesota Dept. of Agriculture — Phosphorus Lawn Fertilizer Law
• Royal Horticultural Society — Lawn care in autumn
• Purdue — Fine fescue maintenance and nitrogen requirements