How to build a raised bed: materials, soil and planting guide

Why a raised bed?

• Drainage: Because the soil sits above ground, rain drains away quickly; root rot is less common in heavy clay gardens.
• Warmer soil: Raised soil warms up faster in spring sun, so you can often sow a few weeks earlier.
• Easier on your back: At 16 in or higher you bend much less; for wheelchair access, build to 24–30 in.
• No compaction: You never step in the bed, so the soil stays loose and roots spread easily.
• Order: Fewer weeds creep in, paths stay clean, and watering and planting plans are simpler.

Choosing a spot

Most vegetables need at least 6–8 hours of direct sun a day. Before you build, watch the garden for a day: which areas are in sun in the morning, at noon and in the evening? Spots with only 4–5 hours suit leafy crops such as lettuce, spinach, parsley and mint better.

• If possible, run beds north–south so both sides get equal sun.
• Pick level ground; on a slope, build the frame in steps.
• Stay close to a tap or water butt; a distant bed gets watered less.
• Keep away from the roots and shade of large trees.

Comparing materials

The frame material decides the budget, the look and how long the bed lasts. Since you will grow food, avoid materials that might leach chemicals into the soil.

For lumber quantities and screw counts on a wooden frame: FixMeasure deck calculator.

⚠️ Do not use wood or pallets of unknown origin for vegetable beds. Old railroad ties are also unsuitable because they contain creosote.

Size: width, height, length

• Width: No more than 4 ft, so you can reach the middle from both sides without stepping in. If you can reach from one side only (against a wall), 2–2.5 ft is enough.
• Height: 10–12 in is enough for most vegetables. On poor or stony ground go to 16–24 in; for a comfortable working height, 24–32 in (estimated).
• Length: As long as you like, but wooden sides longer than 8–10 ft can bow outward under soil pressure; add a middle post or cross brace (estimated).
• Paths: Leave at least 18–24 in between beds, or 30–36 in if a wheelbarrow must pass.

Soil mix

Do not fill the bed with garden soil alone; it compacts over time. A good starting mix:

These ratios are a starting point (estimated). To find how many cubic feet of soil your bed needs, use our Soil calculator. The soil settles by 2–4 in in the first year; top up with 1–2 in of compost every spring.

Step-by-step build

1. Mark the spot: drive stakes at the corners, run a string line and check the square by measuring the diagonals.
2. Clear the ground: remove large stones and perennial weed roots, and loosen the soil with a spade or fork.
3. Build the frame: set the corner posts, screw on the side boards or panels and level them with a spirit level.
4. On a long bed, add a middle post or cross brace so the sides do not bow out.
5. Lay mesh and weed-suppressing cardboard on the base if needed (next section).
6. Fill with the soil mix in layers, watering each layer lightly so it settles.
7. Lay the drip hose or line.
8. Let it settle for a few days, top up any sunken soil, then start planting.

Mesh and cardboard at the base

Mesh: In gardens with moles, voles or gophers, lay galvanized hardware cloth (about 1/2 in mesh) on the base before adding soil, and fix it to the frame at the edges. Bending it up the sides also blocks entry from the edges.

Cardboard: If you build on lawn or weedy ground, lay overlapping plain, unprinted cardboard with tape removed on the base and wet it. It rots within a few months but smothers the weeds below in the meantime. Do not use plastic sheeting; it stops water draining.

Watering

Because a raised bed drains well, it dries out faster than an in-ground bed, especially in summer heat. Drip irrigation is the most efficient answer: water goes straight to the roots, leaves stay dry and disease drops.

• Run drip lines about 12 in apart, parallel along the bed.
• A simple timer can water automatically early in the morning.
• Push a finger 2 in into the soil; if it is dry, it is time to water.
• A mulch of straw, leaves or dry grass clippings cuts evaporation noticeably.

Planting plan and crop rotation

Since you never step in the bed, plants can go in a grid rather than rows, and closer together. Put tall crops (tomatoes, corn, pole beans) on the north edge so they do not shade shorter ones.

Rotation: Do not plant the same plant family in the same bed every year. Split beds into groups and move each group to the next bed each year; this reduces disease and pest build-up and uses nutrients evenly.

Common problems and fixes

Frequently asked questions

Plants that grow well in raised beds

TomatoLettucePepperZucchiniStrawberryCarrotBasilRadish