Pallets are a practical starting point for a raised bed frame

A pallet-built raised bed costs almost nothing if you have access to free pallets, takes a few hours to assemble, and works well for vegetables, herbs, and flowers. The basic idea is straightforward: stack pallets to form four walls, find the corners, line the interior, and fill with soil. Most people can do this with a drill, a level, and a few bolts—no carpentry experience needed.

The catch is that not all pallets are safe. Pallets marked with "HT" (heat-treated) are fine; pallets marked "MB" (methyl bromide) were chemically treated and should not touch food crops. You also need to inspect each pallet for rot, mold, and loose boards before you use it. A pallet that looks solid from the top may have soft spots underneath.

Key Takeaways

  • Use only pallets stamped "HT" (heat-treated), never those marked "MB" (methyl bromide), which are treated with pesticides unsafe for food gardens.
  • Inspect every pallet for rot, mold, and loose nails or boards before building, and replace any that show soft wood or dark staining.
  • find the four corners with bolts or lag screws driven through the pallet stringers (the thick inner beams), not just the deck boards.
  • Line the interior with landscape fabric or cardboard to prevent soil from falling through gaps and to slow weed growth from below.
  • A standard pallet bed holds enough soil for shallow-rooted crops like lettuce and herbs, but root vegetables and tomatoes need deeper beds or extra soil layers.

Finding and inspecting pallets

Free pallets are usually available from grocery stores, garden centers, hardware stores, and warehouses—ask the manager if you can take pallets they are discarding. Many businesses are happy to have someone haul them away. Avoid pallets from chemical suppliers, paint stores, or anywhere that handled hazardous materials.

Once you have a pallet, flip it over and look at the underside. Press your thumb into the wood in several spots; if it leaves a dent or the wood feels soft, that pallet has rot and will not hold up through a season. Check for dark stains, mold (usually black or green), and loose or missing nails. A pallet with a few loose deck boards can be repaired by driving nails back in or replacing the board, but a pallet with structural rot in the stringers (the thick beams running lengthwise) should be left behind.

You will need four pallets of the same size and condition. Standard pallets are 48 inches long and 40 inches wide, which makes a bed roughly 4 feet by 3 feet—a good size for one person to reach across and tend.

Preparing the site and laying out the frame

Choose a spot that gets at least six hours of direct sun for vegetables, or four hours for leafy greens and herbs. Clear the ground of grass, weeds, and large rocks. You do not need to remove every stone, but a relatively flat surface makes assembly easier and helps the bed sit level.

Lay out your four pallets in a rectangle on the ground, with the deck boards (the flat surface you walk on) facing up. Arrange them so the corners overlap slightly or meet edge-to-edge. Place a level across the top in two directions to check if the ground is reasonably flat; if one corner sits much higher than the others, you can shim it with a flat stone or dig out a shallow spot to level it.

Once the pallets are positioned, mark the corner locations with chalk or spray paint so you know where to drill when you pick them up to find them.

Securing the corners with bolts or screws

The corners are where the bed will fail if they are not done right. Do not rely on nails or the weight of the soil to hold the corners together. Use either lag bolts (large screws with a hex head, driven with a wrench) or carriage bolts (bolts with a rounded head, secured with a nut and washer on the underside).

Drill through the stringers—the thick inner beams of the pallet—not through the thin deck boards. A typical pallet has three stringers running across the width. Drill at least two holes per corner, one through each of two stringers. Use a drill bit slightly smaller than your bolt diameter, and drill straight through both pallets at the corner.

For lag bolts, drive them in with a socket wrench until snug; do not over-tighten or you may crack the wood. For carriage bolts, push the bolt through from the outside, slide a washer over the end, thread on the nut, and tighten with a wrench while holding the bolt head steady with another wrench on the opposite side. Tighten all bolts evenly so the frame sits square.

Lining the interior to contain soil and block weeds

Landscape fabric or cardboard prevents soil from spilling through the gaps between deck boards and slows weeds from growing up through the bottom of the bed. Cardboard is cheaper and biodegrades over one to two seasons; landscape fabric lasts longer but costs more.

If you use cardboard, lay it flat on the ground inside the frame, overlapping the pieces by a few inches. Wet the cardboard so it stays in place while you fill. If you use landscape fabric, cut a piece large enough to cover the bottom and extend a few inches up the sides, and staple it to the inside of the pallet frame with a staple gun.

Poke a few small holes in the cardboard or fabric to allow water to drain; you do not want standing water pooling at the bottom. If you are building on very weedy ground, lay cardboard or fabric on the soil before you position the pallets, then set the frame on top.

Filling with soil and preparing to plant

A standard four-pallet bed is roughly 10 to 12 inches deep, depending on the pallet thickness. This depth works for lettuce, spinach, herbs, and shallow-rooted flowers. For tomatoes, peppers, root vegetables, and deeper crops, you have two options: fill the bed deeper by stacking soil higher, or add a second layer of pallets on top of the first (which requires additional bolting at the corners).

Fill the bed with a mix of topsoil and compost. A rough ratio is 60 percent topsoil and 40 percent compost, though you can adjust based on what you have available. Avoid filling with only compost, which can settle and compact over time. Wet the soil as you fill so it settles and compacts naturally.

Let the bed sit for a few days before planting so the soil can settle. If the level drops noticeably, add more soil. Once you plant, mulch the surface with 2 to 3 inches of wood chips or straw to retain moisture and suppress weeds.

Maintaining a pallet bed through the seasons

Pallet wood exposed to soil and water will eventually rot. Most pallet beds last three to five years before the wood begins to fail noticeably. You can extend the life by painting or staining the exterior with a non-toxic wood sealant, though this is optional and adds cost and time.

Each season, check the bolts at the corners and tighten them if they have loosened. If a deck board cracks or rots, you can pry it out and replace it with a new board of the same thickness, secured with nails or screws to the stringers. If a stringer begins to rot, the structural integrity of that corner is compromised and you should plan to rebuild that section.

At the end of each growing season, top-dress the bed with 2 to 3 inches of compost. This replenishes nutrients and raises the soil level as it compacts. Over several years, you will need to add more soil to maintain depth.

Frequently Asked Questions

Can I use pallets that were used to ship food or groceries?

Yes. Pallets from grocery stores and food distributors are typically heat-treated and safe for food gardens. Always check for the "HT" stamp and inspect for rot and mold. Avoid pallets from chemical, pesticide, or paint suppliers.

What if I can't find four matching pallets?

Mismatched pallets work fine as long as they are all the same thickness and in good condition. The bed will look less uniform, but it will function the same way. You can paint or stain them different colors if you want them to look intentional.

Do I need to treat the wood with anything to make it last longer?

No, but you can extend the life by explore a non-toxic exterior wood stain or sealant to the outside surfaces before filling. This slows water absorption and rot. Do not use pressure-treated wood sealant or anything with copper compounds, as these can leach into the soil.

How deep should the soil be for different crops?

Lettuce, spinach, and herbs need 6 to 8 inches. Peppers and bush beans need 10 to 12 inches. Tomatoes, carrots, and potatoes need 12 to 18 inches. A standard pallet bed is about 10 to 12 inches deep, so you may need to add a second layer of pallets or use taller pallets for deeper-rooted crops.

What should I do if the corners start to loosen after a season?

Check and tighten the bolts or screws at each corner. Soil weight and seasonal wood movement can cause fasteners to loosen. If bolts keep loosening, you may need to drill new holes slightly offset from the originals and install new bolts, or reinforce the corners with metal L-brackets bolted to the stringers.