Calculators / Garden and firewood
Raised garden bed plans
Put in the size, who works it and what you grow. You get the height, a cut list of boards and posts, and the soil it takes.
Updated · How we check our numbers
Your raised bed
11¼ in tall: 1 × 2x12
A 8 × 4 ft bed 11¼ in tall holds about 27.3 cu ft of soil. For it, buy 3 × 2x12 at 8 ft, 1 × 4x4 at 8 ft.
- Height
- 11¼ in1 × 2x12
- Soil
- 27.3 cu ft10.3 in deep
- Widest to reach
- 4 ftboth sides
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Estimate for planning only, not professional advice. Check the manufacturer’s instructions, your local code and a licensed professional before you buy, build or install. Use at your own risk. Terms.
Soil for these beds27.3 cu ft in bags or bulk
height = at least 10 in of soil; roots for tomatoes and squash (16 to 18 in) carry on into the ground below: 11 in with an inch of rim
walls = 1 × 2x12 (11¼ in) = 11¼ in
soil = 8 × 4 ft × 10.3 in ÷ 12 = 27.3 cu ft a bed
posts every 4 ft or less: 1 along each side
2x12: 3 boards at 8 ft
4x4: 1 boards at 8 ft
Cut list
PS 20 sizes- 2 × long sides2x12 at 96 in2x12
- 2 × ends2x12 at 45 in2x12
- 4 × corner posts4x4 at 11¼ in4x4
- 2 × middle posts4x4 at 11¼ in4x4
Screw each board to the posts with two 3 in exterior screws.
Fork or dig the ground inside the frame before filling, so tomato and squash roots can go past the 11¼ in of the bed.
Cedar, redwood or cypress, or pressure-treated lumber labelled for ground contact (CA, MCA or ACQ). In Oregon State's study copper from treated boards rose only within an inch of the wood and not in the vegetables. Skip railroad ties and old lumber that could be CCA-treated (before 2004).
Illinois Extension suggests half compost, half topsoil. It settles as the compost breaks down, so top it up each year.
Leave 18 to 24 in between beds to walk and kneel, 4 ft if you'll bring a wheelbarrow or cart through (UGA).
How we work it out
height = the soil your crops need (or 24 in for a wheelchair) + 1 in of rim
How deep. UC Master Gardeners give the soil depth crops need: 9 to 12 in for greens and herbs, 12 to 14 in for peppers, peas and short carrots, 16 to 18 in for tomatoes, potatoes, squash, beans and cucumbers. On open ground the roots carry on into the soil below, so UGA's 10 in minimum is enough for the bed itself. On a patio or gravel, the bed is all the soil there is, so it has to hold the full depth.
How wide. 4 ft if you can reach in from both sides, about 2 ft against a fence or wall, and 3 ft for an adult working from a wheelchair (UGA). Wheelchair beds are 24 in tall.
The frame. We pick the fewest 2x boards that reach the height, screwed to 4x4 posts at the corners and at least every 4 ft along the sides so long boards don't bow under wet soil. Beds 18 in or taller get a 2x6 cap to sit on.
Where the numbers come from
- UGA Extension C 1027-4: Raised Garden Bed Dimensions (2022)
- University of Missouri Extension G6985: Raised-Bed Gardening
- University of Illinois Extension: raised bed gardening (2023)
- Oregon State Extension, Clackamas Master Gardeners: raised beds
- UC Master Gardeners of Contra Costa: growing vegetables in containers (soil depth by crop)
- UC IPM Pest Notes 7433: Pocket Gophers
- Oregon State Extension EM 9879: pressure-treated wood in raised beds (2026)
- NIST PS 20: American Softwood Lumber Standard (board sizes)
Guides
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