A raised bed is the easiest way to start growing food, and you can build one in an afternoon with three boards and a box of screws. This guide covers a standard 4 by 8 foot bed, the soil to fill it, and where to save money.
Why a raised bed
Raised beds drain well, warm up earlier in spring, and let you control the soil from day one. They also keep the growing area clearly separate from paths, so the soil never gets compacted by foot traffic.
A width of 4 feet matters more than the length. It lets you reach the center from either side without stepping in the bed.
Materials for one 4×8 bed
| Item | Quantity | Notes |
|---|---|---|
| 2×10 boards, 8 feet long | 3 | Two for the long sides, one cut in half for the ends |
| Exterior wood screws, 3 inch | About 24 | Deck screws resist rust |
| 4×4 post, cut into 10-inch pieces | 4 pieces (optional) | Corner supports for a sturdier frame |
| Plain cardboard | Enough to cover 32 sq ft | Remove tape and labels |
| Soil mix | About 1 cubic yard | Fills the bed to roughly 10 inches |
Tools: a drill, a saw (or ask the lumber yard to make the one cut), a tape measure, and a level.
Choosing the wood
Untreated pine or fir is the cheapest option and usually lasts several seasons. Cedar costs more but resists rot much longer.
Avoid old railroad ties, which contain creosote, and reclaimed lumber of unknown origin. If you use pallets, look for the “HT” stamp, which means the wood was heat-treated rather than chemically treated.
Build it in six steps
- Pick the spot. Choose level ground with at least six hours of direct sun and easy access to water.
- Cut one board in half. You now have two 8-foot sides and two 4-foot ends.
- Screw the frame together. Stand the boards on edge and join each corner with three screws. If you are using corner posts, screw the boards to the posts instead.
- Set and level the frame. Place it in position and dig out high spots until the frame sits flat.
- Lay cardboard on the ground inside. Overlap the pieces and wet them well. This smothers grass and weeds, then breaks down on its own.
- Fill with soil. Add the mix to about an inch below the rim, water it thoroughly, and top up after it settles.
The soil mix
Soil is where most of the cost goes, and it is also what decides how well your plants grow. A reliable mix is:
- About 60% topsoil
- About 30% compost
- About 10% material that keeps the mix loose, such as coarse sand, perlite or aged bark fines
A 4×8 bed filled 10 inches deep needs roughly 27 cubic feet, which is one cubic yard.
Five ways to cut the cost
- Buy soil in bulk. A cubic yard delivered from a landscape supplier usually costs far less than the same volume in bags.
- Fill the bottom third with yard waste. Logs, branches, leaves and grass clippings take up space and slowly turn into soil.
- Make your own compost. It takes a few months, so start a pile now for next season.
- Use offcuts and seconds. Many lumber yards sell slightly warped or short boards at a discount, and a garden bed does not need perfect wood.
- Skip the extras. Liners, corner brackets and decorative caps are optional.
What to plant first
Once the bed is filled and watered, start with forgiving crops. Our list of the easiest vegetables to grow for beginners has ten good choices with planting seasons and days to harvest.
For the bigger picture, including compost, water and food storage, see how to start a self-sufficient backyard.