How to work out pine straw for a bed
Measure each bed and add up the areas. For a curved bed, measure the longest length and the average width, which is close enough at the size of a bale. Then find out what your bale covers. LSU gives a simple way: half a pound per square foot makes a 3 inch layer, so a bale's weight tells you its coverage. If your supplier prints a coverage, use that instead.
Do not treat pine straw like bagged mulch. Depth is not a good way to work it out, because a bale expands when you open it. LSU's 25 pound bale holds 3 cubic feet, and covers 50 square feet at 3 inches, which is 12.5 cubic feet. A volume sum would buy about 4 times too much. That is why this calculator has no depth field.
The sources disagree on depth. LSU recommends an initial 3 inches for shrubs and trees, and slightly less on bedding plants, roses and perennials. Clemson says 2 to 3 inches. Mississippi State's table says 6 to 8 inches for pine needles. Alabama says one bale covers 50 square feet at 5 inches, where LSU says the same area at 3 inches. Take these as a sign that bales differ.
A worked example
Here is a 30 by 15 foot bed with 25 pound bales. These lines come from the same formula the calculator above runs.
30 by 15 ft bed, 25 lb bales
- 30 × 15 = 450 sq ft
- 25 ÷ 0.5 = 50 sq ft a bale
- 450 ÷ 50 = 9 bales for a first layer
- 50 × 3 = 150 sq ft a bale for a top-up
- 450 ÷ 150 = 3 bales for a top-up
For a bed with wood mulch or bark instead, use the mulch calculator, which does work by volume. If you are planting the bed at the same time, the plant spacing calculator counts what goes in it.
Pine straw bales by area
These use LSU's rate, rounded up to whole bales. A heavier bale goes further at that rate, so the same bed takes fewer of them.
| Area | 25 lb bales, first layer | 25 lb bales, top-up | 40 lb bales, first layer |
|---|---|---|---|
| 100 sq ft | 2 | 1 | 2 |
| 250 sq ft | 5 | 2 | 4 |
| 500 sq ft | 10 | 4 | 7 |
| 1000 sq ft | 20 | 7 | 13 |
| 2500 sq ft | 50 | 17 | 32 |
| 5000 sq ft | 100 | 34 | 63 |
Mistakes with pine straw
- Assuming all bales are equal. LSU says bales run from 25 to 51 pounds, and Alabama says they are not a consistent size.
- Buying a first layer every year. LSU says a 1 inch top-up makes a bale go three times as far.
- Piling it against trunks. Mississippi State says to pull mulch back from the trunk about 2 to 3 inches.
- Ignoring the fire note. Mississippi State lists pine needles as a possible fire hazard. We found no sourced distance, so check locally.
- Forgetting the soil. Mississippi State says pine needles can lower soil pH, and Clemson suggests them for acid-loving plants.
Questions
How many square feet does a bale of pine straw cover?
About 50 square feet at 3 inches for a 25 pound bale, by LSU. Alabama also says 50 square feet, but at 5 inches, and says bales are not a consistent size. Heavier bales go further, so ask your supplier what theirs covers.
How many bales of pine straw do I need?
Your bed's area divided by what a bale covers, rounded up. A 30 by 15 foot bed is 450 square feet, which is 9 bales of 25 pounds for a 3 inch first layer. A 1 inch top-up on the same bed is 3 bales.
How thick should pine straw be?
About 3 inches to start, and less on bedding plants, by LSU. Clemson says 2 to 3 inches, and Mississippi State's table says 6 to 8 inches, so the sources disagree. New straw settles. LSU says to top up by about 1 inch once or twice a year.
How many bales of pine straw to cover 1,000 square feet?
About 20 bales of 25 pounds for a 3 inch first layer, on LSU's figures. A 1 inch top-up takes 7. Larger bales cut that down, so a 40 pound bale at the same rate takes 13 for a first layer.
How many bales of pine straw per acre?
About 872 bales of 25 pounds for a 3 inch first layer. An acre is 43,560 square feet, and each bale covers 50 at LSU's rate. Buying that many, ask your supplier for the weight of each bale first, since a heavier bale cuts the count.
How many bales of pine straw in a cubic yard?
No volume sum works, because a bale expands when opened. LSU's 3 cubic foot bale spreads to about 12.5 cubic feet at 3 inches, or about 4 times. Treating it like bagged mulch would have you buying about 4 times too much.
How many bales of pine straw are in a roll?
We could not find a figure we trust, as rolls vary. Ask the supplier for its coverage in square feet, choose that option above and enter the figure. The result then counts rolls instead of bales, and the sum is the same.
This pine straw count is an estimate, because bales are not a consistent size and extension services disagree on depth. Ask your supplier what a bale covers before you order a large amount. Straw settles over time. Mississippi State lists pine needles as a possible fire hazard, so check local guidance on keeping it back from buildings.
Sources and review
- Pine straw makes excellent mulch, LSU AgCenter, 2009.
- Drought-tolerant landscapes for Alabama, ANR-1336, Alabama Cooperative Extension, 2023.
- Mulch, HGIC 1604, Clemson Cooperative Extension, 2016.
- Mulch helps keep your garden and landscape healthy, publication 2301, Mississippi State University Extension, 2020.
Checked in November 2026. Spotted a wrong number? Report it and it goes in the corrections log.
How this is calculated
Every figure below is read from the code that produces the answer, so what is written here is what the calculator ran. The constants were last checked against their sources in November 2026.
The arithmetic
Coverage
Coverage = Bale weight ÷ 0.5
- 0.5
- LSU's pounds per square foot for 3 inches
Worked through: 25 ÷ 0.5 = 50 sq ft
Bales
Bales = Bed area ÷ Coverage, rounded up
- Coverage
- Three times as much for a top-up
Worked through: 450 ÷ 50 = 9 bales
The constants, and where they come from
POUNDS_PER_SQ_FT
Published figurePounds of pine straw per square foot for a 3 inch layer
Applies to: Louisiana bales, which LSU says weigh 25 to 51 pounds. Alabama says bales are not a consistent size
Source: Pine straw makes excellent mulch, LSU AgCenter, published 2009-03, read 2026-11. This source is about 17 years old, and it is the one the figure rests on.
Also from: Drought-tolerant landscapes for Alabama, ANR-1336, Alabama Cooperative Extension, published 2023-06, read 2026-11.
LSU prints this rate and says a 25 pound bale covers 50 square feet at 3 inches, which agree. Alabama says one bale covers 50 square feet at 5 inches, so extension sources differ.
TOP_UP_FACTOR
Published figureHow much further a bale goes when topping up
Applies to: A top-up of about 1 inch, by LSU
Source: Pine straw makes excellent mulch, LSU AgCenter, published 2009-03, read 2026-11. This source is about 17 years old, and it is the one the figure rests on.
LSU says yearly or twice-yearly reapplication can be to a depth of 1 inch, and that one bale should then go three times as far as in a first layer.
What the labels mean
- Published figure:
- taken directly from the source named beside it.
If a figure here looks wrong, it may be. Tell us what you found and we will check it against the source and publish a correction if it needs one. How constants are chosen and how often they are reviewed is set out in our methodology.
How to use the pine straw calculator
- 1
Measure the bed
- 2
Say if this is a first layer or a top-up
- 3
Weigh a bale or ask your supplier what it covers
- 4
Round up to whole bales
- 5
Pull the straw back from trunks as you spread it
What this calculator assumes
Every estimate here rests on the assumptions below. Where your job differs from one of them, the figure will differ too.
- A first layer is 3 inches at half a pound per square foot, by LSU
- A top-up of 1 inch makes a bale go three times as far, by LSU
- Coverage is by weight or by your supplier's figure, and not by volume
Pro tips
- Weigh one bale, or ask for its weight, before a large order
- Use it on a slope, where Clemson says it stays in place better than most mulches
- Use it around acid-loving trees and shrubs, as Clemson suggests