Spread
- 3.13lb per 1,000 sq ft
- 35cups, about
- 2–3feedings a year
- Spread 17.6 lb of your fertilizer on 5,625 sq ft. That gives 5.63 lb of nitrogen.
- That is 1 bag of 40 lb. One bag covers about 12,800 sq ft.
- Tall fescue needs 2 to 3 lb of nitrogen a year for each 1,000 sq ft. At this rate, feed it 2 to 3 times a year.
How much nitrogen your grass needs
Pounds of nitrogen a year for each 1,000 sq ft. The low end is for a lawn with little care. The high end is for more care.Grams of nitrogen a year for each sq m. The low end is for a lawn with little care. The high end is for more care.
| Grass | Nitrogen a year | Feedings at 1 lb4.9 g | Use |
|---|---|---|---|
| Kentucky bluegrassCool-season, Penn State | 2 to 4 lb9.8 to 19.5 g | 2 to 4 | |
| Perennial ryegrassCool-season, Penn State | 2 to 4 lb9.8 to 19.5 g | 2 to 4 | |
| Tall fescueCool-season, Penn State | 2 to 3 lb9.8 to 14.6 g | 2 to 3 | |
| Fine fescueCool-season, Penn State | 1 to 2 lb4.9 to 9.8 g | 1 to 2 | |
| BermudaWarm-season, Clemson | 3 to 5 lb14.6 to 24.4 g | 3 to 5 | |
| ZoysiaWarm-season, Clemson | 3 to 5 lb14.6 to 24.4 g | 3 to 5 | |
| St. AugustineWarm-season, Clemson | 1 to 4 lb4.9 to 19.5 g | 1 to 4 | |
| CentipedeWarm-season, Clemson | 1 to 2 lb4.9 to 9.8 g | 1 to 2 |
Cool-season: Penn State. Warm-season: Clemson HGIC 1201. Penn State gives lower figures for bermuda and zoysia in Pennsylvania. Clemson says not to give centipede more than 2 lb a year.
How to figure out how much fertilizer
Divide the nitrogen you want by the first number on the bag, as a decimal.
1 lb ÷ 0.32 = 3.1 lb of 32-0-4 for each 1,000 sq ft.
Then times your lawn size, divided by 1,000. A 5,625 sq ft lawn needs about 17.6 lb. This is Iowa State's example.
Some guides say it a simple way. Divide 100 by the first number. That gives pounds for 1 lb of nitrogen on 1,000 sq ft. For ½ lb, divide 50.
How much at one time
Do not use more than 1 lb4.9 g of nitrogen at a time for each 1,000 sq ftsq m. Purdue says too much fast-acting food can hurt grass.
Slow-release food is gentler. Clemson says up to 2 lb9.8 g when all of the nitrogen is slow-release.
How the math works
- Area. Length times width. For a circle, half the width times itself, times 3.1416. One meter is 3.28084 feet.
- Per 1,000 sq ft. Nitrogen you want divided by the first number on the bag, as a decimal.
- Your lawn. That times your area in sq ft, divided by 1,000.
- Bags. Pounds divided by the bag weight, rounded up.
- Cups. Iowa State says 1 cup of most dry fertilizer weighs about 0.5 lb. It is a rough guide.
- Feedings. Nitrogen your grass needs a year, divided by what you give each time.
- Metric. 1 lb for each 1,000 sq ft is 4.88 g for each sq m. One kg is 2.2 lb.
Questions
How much fertilizer do I need for my lawn?
Divide 1 by the first number on the bag, as a decimal. For 32-0-4, that is 3.1 lb for each 1,000 sq ft. Type your lawn above to get yours.
How much fertilizer per 1,000 square feet?
Enough to give ½ to 1 lb of nitrogen. With a 10-10-10 bag, that is 5 to 10 lb. With a 32-0-4 bag, it is 1.6 to 3.1 lb.
How many times a year should I fertilize?
It depends on the grass. Tall fescue needs 2 to 3 lb of nitrogen a year. At 1 lb a time, that is 2 to 3 times. Bermuda needs 3 to 5.
What do the three numbers on a bag mean?
They are the percent of nitrogen, phosphorus and potash. The first one is nitrogen. Lawn guides count the nitrogen, so this calculator uses it.
How much area does a bag cover?
Times the bag weight by the first number, as a decimal. That is the pounds of nitrogen in it. A 40 lb bag of 32-0-4 has about 12.8 lb. At 1 lb a time, it covers about 12,800 sq ft.
Sources
- Iowa State Yard and Garden, How to Calculate Fertilizer Rates for the Lawnreviewed Apr 2026The math; 1 cup weighs about 0.5 lb
- Purdue PPP-155, A Simple Procedure for Fertilizing Cool-Season LawnsundatedNo more than 1 lb of nitrogen at a time
- Penn State AASL, Home Lawn to MaintainDec 2017Nitrogen a year for cool-season grass; 1 lb at a time
- Penn State Extension, Turfgrass FertilizationNov 2016Nitrogen a year by grass; slow-release above 1 lb
- Clemson HGIC 1201, Fertilizing LawnsOct 2019Nitrogen a year for warm-season grass; 2 lb slow-release
- University of Missouri G6705Apr 2025Divide 100 by the first number