How much top dressing you need
cubic feet = lawn area (sq ft) × depth (in) ÷ 12 cubic yards = cubic feet ÷ 27
Worked example (the default): 1,000 sq ft of lawn at ¼ inch.
- 50 × 20 ft = 1,000 square feet
- 1,000 × 0.25 ÷ 12 = 20.8 cubic feet = 0.77 cubic yards
- With 10% extra: 22.9 cubic feet = 0.85 cubic yards
- In bags: 23 bags of 1 cubic foot or 12 bags of 2 cubic feet
Fractions as decimals: ⅛ = 0.125, ¼ = 0.25, ⅜ = 0.375, ½ = 0.5.
Top dressing chart by lawn size
Cubic feet, then cubic yards in brackets. No extra included.
| Lawn area | ⅛ inch | ¼ inch | ½ inch |
|---|---|---|---|
| 500 sq ft | 5.2 (0.19) | 10.4 (0.39) | 20.8 (0.77) |
| 1,000 sq ft | 10.4 (0.39) | 20.8 (0.77) | 41.7 (1.54) |
| 2,500 sq ft | 26.0 (0.96) | 52.1 (1.93) | 104.2 (3.86) |
| 5,000 sq ft | 52.1 (1.93) | 104.2 (3.86) | 208.3 (7.72) |
| 10,000 sq ft | 104.2 (3.86) | 208.3 (7.72) | 416.7 (15.43) |
At these depths a cubic yard goes a long way: 1,296 square feet at ¼ inch, and 2,592 square feet at ⅛ inch.
Leveling low spots
Measure each dip separately. Lay a straight board across it and measure the gap at a few points to get an average depth.
Example: a dip 6 ft × 4 ft, averaging 1 inch deep.
- Area: 6 × 4 = 24 square feet
- Volume: 24 × 1 ÷ 12 = 2 cubic feet, so two 1-cubic-foot bags
- Spread it in two passes of about ½ inch, a few weeks apart, so the grass can grow through each layer
Add up all the dips, then add the overall top dressing if you are doing both.
What to top dress with
The calculator’s top-dressing / lawn-leveling mix setting uses about 1.1 to 1.4 tons per cubic yard for the weight, which suits sand and sandy soil blends. Switch the material to Compost for a lighter organic top dressing.
| Material | Used for | Watch out for |
|---|---|---|
| Screened compost | Adding organic matter, improving thin lawns | Must be fine and well finished so it works down between the blades. |
| Sandy loam topsoil | Light leveling, general top dressing | Should be screened and free of stones and weed seeds. |
| Sand / soil / compost blend | Leveling and smoothing | Ask the supplier what is in it and in what ratio. |
| Sand | Leveling, mainly on sandy-soil lawns | Repeated sand over clay can create layers that drain poorly. |
A widely given rule of thumb: match the top dressing to the soil you already have, so water moves through evenly.
How to top dress
- Mow a little shorter than usual and rake out thatch if needed.
- Tip small heaps of material across the lawn, rather than one big pile.
- Spread thinly with a shovel flick, then work it in with the back of a leveling rake or a stiff broom until the grass blades show through.
- Water lightly to settle it.
- Repeat in a few weeks for low spots that need more.
Early in the growing season, when the grass is actively growing, is the usual time, so it recovers quickly.
If a dip is from a sinking drain line, settling trench or something underground, find out why before you fill it. In the US, call 811 before you dig.
Questions gardeners ask
- How much top dressing do I need per 1,000 square feet?
- About 10.4 cubic feet (0.39 cubic yards) at 1/8 inch, 20.8 cubic feet (0.77 cubic yards) at 1/4 inch and 41.7 cubic feet (1.54 cubic yards) at 1/2 inch.
- How thick should lawn top dressing be?
- Usually 1/8 to 1/4 inch per application, so the grass blades still show through after you rake it in. For low spots, up to about 1/2 inch at a time, then wait for the grass to grow through before adding more.
- What should I use to top dress a lawn?
- Common choices are screened compost, sandy loam topsoil, sand, or a blend. Many turf guides suggest choosing a material similar in texture to your existing soil, so you don't create layers that slow drainage.
- How do I level a lawn with deep dips?
- Fill in stages of about half an inch, letting the grass grow through each time. For hollows deeper than a couple of inches, many people cut and fold back the turf, fill underneath with soil, firm it, and lay the turf back down.