How Much Lawn Fertilizer Do I Need? Pounds and Bags by Lawn Size
Part of the project planner: Planning a new lawn and garden beds.
The amount of fertilizer for a lawn depends on the nitrogen percentage on the bag: you divide the pounds of nitrogen you want by that percentage. For 1 pound of nitrogen per 1,000 sq ft with a 28% nitrogen fertilizer you need 3.6 pounds per 1,000 sq ft, so 17.9 pounds for 5,000 sq ft (2 bags of 15 pounds). The lawn fertilizer calculator works it out for your own lawn, product and rate.
Fertilizer by lawn size
For a 28% nitrogen fertilizer at 1 pound of nitrogen per 1,000 sq ft:
| Lawn | Fertilizer | Nitrogen applied | 15 lb bags | 40 lb bags |
|---|---|---|---|---|
| 1,000 sq ft | 3.6 lb | 1.0 lb | 1 of 15 lb | 1 of 40 lb |
| 2,500 sq ft | 8.9 lb | 2.5 lb | 1 of 15 lb | 1 of 40 lb |
| 5,000 sq ft | 17.9 lb | 5.0 lb | 2 of 15 lb | 1 of 40 lb |
| 10,000 sq ft | 35.7 lb | 10.0 lb | 3 of 15 lb | 1 of 40 lb |
| 15,000 sq ft | 53.6 lb | 15.0 lb | 4 of 15 lb | 2 of 40 lb |
How the nitrogen percentage changes the amount
For a 5,000 sq ft lawn at 1 pound of nitrogen per 1,000 sq ft (5 pounds of nitrogen):
| Fertilizer | Pounds needed | Per 1,000 sq ft |
|---|---|---|
| 10% nitrogen | 50.0 lb | 10.0 lb |
| 16% nitrogen | 31.3 lb | 6.3 lb |
| 20% nitrogen | 25.0 lb | 5.0 lb |
| 28% nitrogen | 17.9 lb | 3.6 lb |
| 32% nitrogen | 15.6 lb | 3.1 lb |
How much nitrogen to apply
| Rate | Fertilizer for 5,000 sq ft (28% N) |
|---|---|
| 0.5 lb per 1,000 sq ft | 8.9 lb |
| 0.75 lb per 1,000 sq ft | 13.4 lb |
| 1 lb per 1,000 sq ft | 17.9 lb |
| 1.5 lb per 1,000 sq ft | 26.8 lb |
- 0.5 to 1 pound of nitrogen per 1,000 sq ft per application is typical for quick-release fertilizer.
- Slow-release fertilizer can be applied at 1 to 1.5 pounds, since it releases the nitrogen over weeks.
- The total for the year is about 2 to 4 pounds per 1,000 sq ft for most lawns, depending on the grass and the climate.
How to apply it
- Calibrate the spreader to the product, using the setting on the bag, and apply half in one direction and half across.
- Apply it to dry grass and water it in, unless the label says otherwise. Sweep any fertilizer off paths and drives.
- Do not apply before a heavy rain, which washes it into drains and waterways.
- Test the soil every few years to see if the pH or other nutrients need attention.
See the grass seed calculator for seeding. Fertilizer rules vary by state and town, and some places restrict nitrogen or phosphorus: check the local rules and read the label.
Frequently asked questions
How much fertilizer do I need per 1,000 square feet?
Divide the pounds of nitrogen you want (usually 1 pound per 1,000 sq ft) by the nitrogen percentage on the bag. With 28% nitrogen that is 3.6 pounds of fertilizer per 1,000 sq ft.
How many bags of fertilizer for 5,000 square feet?
17.9 pounds of a 28% nitrogen fertilizer for 1 pound of nitrogen per 1,000 sq ft, which is 2 bags of 15 pounds or 1 bag of 40 pounds.
What do the three numbers on a fertilizer bag mean?
They are the percentages of nitrogen (N), phosphate (P₂O₅) and potash (K₂O) by weight. A 28-0-0 fertilizer is 28% nitrogen. Lawns mostly need nitrogen.
How often should I fertilize a lawn?
Cool-season lawns are usually fed 2 to 4 times a year, mostly in fall and spring, and warm-season lawns 2 to 4 times in the growing season. Do not fertilize a dormant or drought-stressed lawn.
How much nitrogen per application?
About 0.5 to 1 pound of nitrogen per 1,000 square feet each time, and up to 1.5 pounds for slow-release products. Follow the label: too much burns the grass.
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.