# Raised garden bed calculator

> 8′ × 4′ raised bed: 6 × 8′ cedar 2×6 boards, 1.25 cu yd of soil, and the corner posts and screws. Boards cut from the fewest pieces, corner posts, screws, a liner against weeds or gophers, and the soil by the bag or by the yard.

## What to buy (8′ × 4′ raised bed)

Every line shows the quantity to buy and how StudSheet got it: the spacing, the waste and the package size, so you can check it before the supply house or the quote.

| Buy | Material | How StudSheet counts it | What it is for |
|---|---|---|---|
| **6 boards** | Cedar 2×6 (2×6 × 8′) | 2 courses of 2×6 (5-1/2″) for 11″ × 2 sides: 4 × 96″ (1 a board) + 4 × 45″ (2 a board). | Rot-resistant and untreated: the usual board for food beds. Actually 1½″ × 5½″. |
| **1 post** | Cedar 4×4 (4×4 × 8′) | 4 corner posts a bed = 4, each 11″ long, 8 from each 8′ post. | Corner and middle posts inside a cedar bed. Actually 3½″ × 3½″. |
| **≈32 screws (1 box of 100)** | Coated deck screws (3″ exterior, coated or stainless) | Two at each board end into the corner posts. Coated or stainless: treated wood eats plain steel, and cedar streaks black around it. | Exterior-rated screws for treads and risers. |
| **1.25 cu yd delivered** | Garden soil blend, bulk (garden soil and compost blend) | 8′ × 4′ × 11″ + 10% for settling = 32.3 cu ft. In bulk it costs far less than 22 bags; have it dumped on a tarp near the beds. | Soil and compost blend by the yard (by the cubic metre in Canada) from a landscape yard, dumped where the truck can reach. |

### In Canada (2.44 m × 1.22 m raised bed)

Set to Canada, the Sheet works the job out again for Ontario: metric sizes, bag sizes, the frost depth and the code notes. It doesn't just convert feet to meters. The first lines:

- **6 boards, Cedar 2×6:** 2 courses of 2×6 (140 mm) for 279 mm × 2 sides: 4 × 2.44 m (1 a board) + 4 × 1.14 m (2 a board).
- **1 post, Cedar 4×4:** 4 corner posts a bed = 4, each 279 mm long, 8 from each 2.44 m post.
- **≈32 screws (1 box of 100), Coated deck screws:** Two at each board end into the corner posts. Coated or stainless: treated wood eats plain steel, and cedar streaks black around it.
- **1 m³ delivered, Garden soil blend, bulk:** 2.44 m × 1.22 m × 279 mm + 10% for settling = 0.91 m³. In bulk it costs far less than 22 bags; have it dumped on a tarp near the beds.

## The steps, in order

> **DIY OK: you can do this yourself with standard tools.** About 3–4 hours of work for this example.

1. Pick a sunny, level spot (6–8 hours of sun for vegetables); level the ground where the boards will sit — no need to dig the whole bed.
2. Cut the boards (96″, 45″) and the posts (11″); pre-drill near the board ends so they don’t split.
3. Build each frame upside down on a flat surface: long boards full length, short boards between them, screwed into the corner posts inside the corners.
4. Set the frame: check it’s square (equal diagonals) and level.
5. Line the bottom with flattened cardboard (tape and labels off), overlapped 6″, and wet it down.
6. Fill: soil to about 1″ below the top; water it in and top it up after it settles.

## Tools (14)

Must-have tools first, then the ones that help and the ones to rent for the day.

| Tool | Need | Why |
|---|---|---|
| **Circular saw** | **Must have** | Cuts the boards and posts |
| **Miter saw** | Good to have | Square, repeatable cuts |
| **Speed square** | **Must have** | Triangle square for marking square and angled cuts on lumber. |
| **Cordless drill/driver** | **Must have** | Pre-drills the board ends so they don’t split |
| **Impact driver** | **Must have** | Drives the 3″ screws |
| **Clamps (2)** | Good to have | Hold the boards to the posts while you screw |
| **Tape measure (25 ft)** | **Must have** | The red boxes every 16″ on the blade are stud spacing. |
| **Carpenter's pencil** | **Must have** | Flat, doesn't roll away, marks rough lumber. |
| **4-ft level** | **Must have** | Levels the frame side to side and end to end |
| **Square shovel** | **Must have** | Levels the ground under the boards |
| **Landscape rake** | **Must have** | Spreads gravel and soil level. |
| **Wheelbarrow** | **Must have** | Moves 1.2 cu yd of soil from the pile |
| **Work gloves** | **Must have** | Tack strip, block and lumber shred hands. |
| **Safety glasses** | **Must have** | Every cut, every nail, every time. |

## Mistakes and how the math works

### Mistakes that cost a callback or a second trip

- **A bed wider than you can reach:** Past about 4 ft you end up stepping in and packing the soil. Two narrow beds beat one wide one.
- **Long sides with no brace:** Wet soil bows a long side outward in a season. A middle post every 8 ft (every 4 ft on tall beds).
- **Old railroad ties or CCA lumber:** Creosote and arsenic-treated wood don’t belong next to food. Cedar or modern treated lumber.
- **Filling with plain topsoil:** It compacts into a brick in a raised bed. Use a raised-bed mix or soil blended with compost.

### What the calculator assumes

- 1 bed, 8′ × 4′ × 11″: 2 courses of cedar 2×6 (5-1/2″ wide), the short sides between the long ones.
- Boards packed into 8′, 10′, 12′, 16′ lengths with the least lumber bought; long sides past 16′ splice at a middle post.
- Posts the height of the bed, sitting on the ground inside the corners; a middle post every 8 ft of long side (every 4 ft at 22″ and taller); cross-ties on long beds 16½″ and taller.
- Soil: the bed’s volume + 10% for settling (typical); 1.5 cu ft bags, or bulk past about a cubic yard.

## Code, permits and safety

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the [code reference](https://studsheet.com/codes) has more. Always confirm with your building department.

- **Permits:** a job like this usually needs none, but towns set their own rules. Ask your building department if you're not sure.

## Questions

### What materials do I need to build a raised garden bed?

For the worked example, a 8′ × 4′ raised bed, the Sheet counts 4 lines with waste included, starting with cedar 2×6 (6 boards), cedar 4×4 (1 post), coated deck screws (≈32 screws (1 box of 100)), garden soil blend, bulk (1.25 cu yd delivered). Each line's math is in the table above. Put in your own sizes in the [raised bed calculator](https://app.studsheet.com/p/garden) and every line is counted again.

### How long does it take to build a raised garden bed, and can I do it myself?

About 3 to 4 hours for the worked example, in 6 steps. StudSheet stamps it **DIY OK**: you can do this.

### What tools do I need to build a raised garden bed?

14 in all. The must-haves start with circular saw, speed square, cordless drill/driver, impact driver, tape measure (25 ft), carpenter's pencil. On the Sheet you mark each one as owned, to buy or to rent.

## Ask about it

Stuck while you build a raised garden bed? Ask in the [Raised beds and gardens group](https://studsheet.com/forum/raised-beds) of the StudSheet community with this Sheet attached. Homeowners who've done it and verified pros answer, and anyone can read it.

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