How to Build a 4×8 Raised Bed: Materials & Cut List
By Rowan Plank · Published September 28, 2026
A 4×8 ft raised bed about 11 inches tall takes six 2×6×8 ft boards, four short corner posts, two stakes and about 40 exterior screws. With basic tools, it takes an afternoon. The finished bed holds about 29 cubic feet of soil.
What materials do you need?
For one 4×8 ft bed, two boards high (2 × 5½ in = 11 in):
| Item | Quantity | Used for |
|---|---|---|
| 2×6 × 8 ft boards (ground-contact treated or cedar) | 6 | Two rows: 4 long sides, 4 short ends |
| 4×4 × 8 ft post | 1 | Four 11 in corner posts |
| 2×4 × 8 ft board | 1 | Two 24 in mid-side stakes |
| 3 in exterior screws | ~40 | 2 per board end at each corner + stakes |
Buy one extra 2×6 if any boards at the store are badly warped or split. The Raised Bed Lumber Calculator adds a 10% margin by default, which rounds this bed up to 7 boards.
Not sure which lumber to buy? See the best wood for raised beds. Short version: ground-contact pressure-treated is the long-lasting budget pick, and cedar is the untreated one.
Tools: circular saw or hand saw, drill/driver, tape measure, speed square, level, shovel.
What's the cut list?
| Cut | From | Pieces | Length |
|---|---|---|---|
| Long sides | 2×6 × 8 ft | 4 | 96 in (no cut) |
| Short ends | 2×6 × 8 ft (cut in half) | 4 | 48 in |
| Corner posts | 4×4 × 8 ft | 4 | 11 in |
| Mid-side stakes | 2×4 × 8 ft | 2 | 24 in, pointed on one end |
With the ends butted against the inside of the long sides, the outside of the bed measures about 96 × 51 in. If you need exactly 48 in outside, cut the ends to 45 in instead.
How do you build it?
- Pick the spot. Raised beds need at least 6 hours of direct sun a day (Clemson Extension). Check that a hose reaches.
- Clear and loosen the ground. Remove sod or smother it with cardboard. Oregon State Extension recommends loosening the native soil at least 6 in deep so roots can grow past the bed.
- Build the ends first. Stand two corner posts on a flat surface. Screw one 48 in end board to them, flush with the top of the posts, with 2 screws into each post. Add the second row below it. Repeat for the other end.
- Add the long sides. Stand the two end frames up 96 in apart. Screw the long boards across the outside of the posts, 2 screws per board end. Check the corners with a speed square as you go.
- Level it. Set the frame in place and check it with a level along both sides. Dig out under high spots rather than propping up low ones, so the bottom board sits on soil everywhere.
- Add the mid-side stakes. Drive a 2×4 stake against the inside of each long side at the 4 ft mark, and screw it to both boards. Oregon State Extension recommends reinforcing sides longer than about 6 ft, because wet soil pushes 8 ft boards outward.
- Fill it. Use a blended raised-bed mix, not plain topsoil. For the amount, see how much soil you need.
Use screws rated for treated lumber
The copper in modern pressure-treated wood corrodes ordinary steel screws. Look for exterior screws labeled for treated lumber (coated or hot-dip galvanized). Stainless steel works too.
How much soil does it take?
At 11 inches deep, the bed holds 8 × 4 × (11 ÷ 12) ≈ 29.3 cu ft — about 1.1 cubic yards, or 15 bags of 2 cu ft before settling. Add about 10% to cover settling. The Raised Bed Soil Calculator does the math for any size, with bag counts and a topsoil/compost mix.
How do you make it taller?
Add a third row of 2×6 boards for a 16½ in bed: three more 8 ft boards, 16½ in corner posts, and 16 more screws. For beds over about 18 in, Oregon State Extension recommends extra reinforcement — use 2×8 or 2×10 boards and a stake at every 4 ft. See how deep a raised bed should be to decide whether you need the height.
Sources: Raised Bed Gardening — OSU Extension, Raised Beds — Clemson HGIC, Pressure-treated wood for raised bed construction — OSU Extension.
FAQ
How much does it cost to build a 4×8 raised bed?
It depends on your lumber prices. The materials are six 2×6×8 ft boards, one 4×4×8 ft post, one 2×4×8 ft board for stakes, and about 40 exterior screws. Price those at your local store and enter them in the Raised Bed Lumber Calculator to get your total.
What screws should I use for a raised bed?
3-inch exterior screws rated for pressure-treated lumber, such as coated or hot-dip galvanized deck screws. Modern treated wood is corrosive to plain steel, and interior screws rust through within a season or two.
Should I put cardboard at the bottom of a raised bed?
You can. A layer of plain cardboard over grass smothers it and breaks down within a season. Remove tape and glossy labels first. It's optional if you dig or loosen the soil before filling.
How do I keep gophers out of a raised bed?
Staple galvanized hardware cloth (½-inch mesh) across the bottom of the frame before you set it in place. It lets water and roots through but stops burrowing animals.