How to Use a Premium Cedar Board 3 ft x 5.5 in in Raised Beds

By Greenes Fence Company: Cedar Raised Garden Beds ... | Published: 2026-11-01

Category: How-to Guides

Turn 3 ft premium cedar boards into sturdy raised bed sides. Plan cuts, set posts, and fasten boards with a simple, repeatable method.

Quick answer

Use the 3 ft premium cedar board as horizontal raised bed sides, stacked two to four boards high and fastened to posts set at each corner and every 3 ft along long runs. Plan your cuts around the 3 ft length so each board spans a full side or a clean 3 ft section.

Why the 3 ft length sets your layout

A 3 ft board is short enough to handle alone but long enough to form a full side of a compact bed. That makes it a natural fit for a 3 ft x 3 ft or 3 ft x 6 ft footprint, where each side is either one board or two boards end to end.

If you want a deeper bed, stack boards rather than buying longer stock. Two boards give roughly 11 in of height, three give about 16.5 in, and four give about 22 in, assuming you keep a small gap between courses for drainage and air.

The trade-off: rough, unsanded cedar

This board is rough and unsanded, so it grips fasteners well and accepts stain, but it can splinter during handling. Wear gloves and sand any edge you will touch often, especially the top course.

The 3/4 in thickness is sturdy for a residential bed but not a structural beam. Keep posts close enough that boards do not bow outward under soil pressure, and avoid using these boards as the only support for a tall, wide bed.

Step-by-step: build raised bed sides with 3 ft cedar boards

1. Choose your bed footprint: Decide between a 3 ft x 3 ft bed (one board per side) or a 3 ft x 6 ft bed (two boards per long side). Mark the corners with stakes and check that the diagonals match before digging. If the diagonals differ by more than about 1 in, adjust the stakes before setting posts.
2. Set posts at corners and midpoints: Place a post at each corner and add a midpoint post on any side longer than 3 ft. Set posts so their tops sit at your planned bed height plus a little extra for the top cap if you add one. A missing midpoint post on a 6 ft side is the most common cause of bowed cedar board raised bed sides.
3. Make a cedar board cutting plan: Lay out the boards dry before cutting. For a 3 ft side, use full 3 ft boards. For a 6 ft side, butt two 3 ft boards at the midpoint post so each board is fully supported. Avoid joints that fall between posts; a floating butt joint will separate as the soil settles.
4. Pre-drill and fasten the first course: Start with the bottom board, leaving a small gap above grade for drainage and air. Pre-drill pilot holes near board ends to reduce splitting, then fasten through the board into the post with exterior-rated screws. Keep fasteners at least 1 in from board ends; closer placement splits rough cedar.
5. Stack and stagger the remaining courses: Add boards upward, leaving a consistent gap between courses. Stagger vertical joints from the course below so no seam lines up, and check each course with a level as you go. If a board bows, flip it end for end before fastening rather than forcing it flat.
6. Finish edges and optional stain: Sand the top edges you will brush against. The untreated cedar can be left natural or stained; if you stain, follow the product's instructions and test on an offcut first. Stain before filling the bed, not after, so runoff does not reach your soil.

Product facts

Premium Cedar Board 3 ft x 5.5 in (3/4 in Thick) RCB36P: Rough, unsanded cedar board measuring 3/4 in thick x 5.5 in high x 3 ft long, model RCB36P. The 5.5 in face height lets you calculate bed depth by counting courses, and the 3 ft length sets a natural side span for compact beds.
Premium Cedar Board 3 ft x 5.5 in (3/4 in Thick) RCB36P