Straw Calculator
Calculate how many bales of straw you need to cover new grass seed or bare soil for erosion control, plus total cost.
How this calculator works
Straw is spread as a light protective cover over freshly seeded soil to hold moisture and reduce erosion while grass germinates. This calculator divides your area by the standard coverage of 80 square feet per bale for a light seeding-cover layer, then rounds up to a whole bale.
Formula: Bales = Area sq ft ÷ 80 sq ft per bale (rounded up to a whole bale).
Worked example
A 50 ft × 20 ft new-lawn area (1,000 sq ft):
- Bales needed: 1,000 ÷ 80 = 12.5 → 13 bundles
- At $9/bale, that’s $117.00.
Coverage reference
| Area | Bales needed |
|---|---|
| 25 × 10 ft | 4 bundles |
| 50 × 20 ft | 13 bundles |
| 100 × 40 ft | 50 bundles |
How to measure your area
Measure the length and width of the area you just seeded and multiply for the total square footage, matching the footprint you used on the grass seed calculator so the two line up. Split irregular yards into rectangular sections and total them, since straw coverage needs to match the exact seeded area rather than a rough estimate.
Frequently asked questions
How much area does one bale of straw cover for seeding?
One bale lightly covers roughly 80 square feet as a seeding cover mulch — the rate used by this calculator. That's a thin, loose layer meant to shade the soil and hold moisture without smothering emerging grass, not the thicker mat used for erosion-control blankets.
What's the difference between straw and hay for lawn seeding?
Straw is the dried, hollow stalk left after cereal grain (wheat, oats, barley) is harvested and contains no seed heads. Hay is cut and dried grass or legume forage that typically still carries seed heads, so spreading hay on a new lawn risks introducing weeds and unwanted grass species along with it.
When should I remove the straw cover after seeding?
You generally don't need to remove it — as new grass grows through the straw, mowing at the recommended first-cut height chops and redistributes what's left, and the remainder breaks down into the soil. Just avoid piling it so thick that seedlings can't push through.
Should I add extra straw for wind or slope?
On windy sites or steep slopes, a light crimping pass (working the straw shallowly into the soil surface with a rake or roller) holds it far better than adding more material, so there's no waste toggle here. For serious slope erosion control, a tackified straw blanket product is a better fit than loose bales.
How does this differ from the pine straw calculator?
Pine straw is a decorative, long-lasting landscape bed mulch used at roughly 50 sq ft of coverage per bale, while straw here is a thin, temporary seeding cover at about 80 sq ft per bale that's meant to break down and disappear as the lawn establishes.
Estimates only. Verify quantities with your supplier before purchasing.