Planning Your Garden Location
Pick a spot for your garden bed. Keep in mind many types of plants — such as vegetables — need plenty of sun. Watch our Gardening Basics Video — How Should I Design My Vegetable Garden? — for tips on choosing a good location.
You're reading: How to Build a Raised Garden Bed
Building the Garden Bed
The bed frame can be as simple as 2 x 4s on top of the ground, or even patio retaining wall blocks. The size is up to you. A bed that’s at least 6 inches high provides ease of access and gives roots plenty of room to grow. These instructions describe building a 4-foot by 6-foot by 10-1/2-inch bed with 2 x 4 untreated lumber. Untreated lumber isn’t rot-resistant, but it’s a good option for edibles.
Measure and mark the length of the walls and cut the boards. Measure and cut 2 x 4s for corner posts to support the walls. They should be the height of the garden bed wall. You can also cut posts to install along the walls for additional strength.
Good to Know
For our frame, we cut six 6-foot boards, six 3-foot 9-inch boards and ten 10-1/2-inch support posts. You can build this bed with ten 2 x 4 x 10 boards.
Clamp together the boards for each wall. Set the corner posts on top of the wall boards, flush with the ends of the 6-foot walls and set back 1-1/2 inches from the ends of the shorter walls. Drill pilot holes and attach the posts with screws. If you cut additional posts, attach them as well.
Preparing Your Location
Mark the location for your garden bed and remove the grass from this area. You can then add the finishing touches to the frame.
Place the frame in position and outline it with a shovel. Setting up the bed on the ground rather than a hard surface — such as concrete — allows proper root growth and drainage.
Good to Know
A large frame is heavy and unwieldy. You may need a helper when it’s time to move it.
Set the frame aside to remove the grass. Loosen the dirt with a spading fork to help your new plants’ roots grow deeply into the ground.
Before you set the bed in place, staple wide-mesh hardware cloth to the bottom of the frame. The mesh helps keep weeds out, but earthworms can still get in to enrich the soil. As an alternative to hardware cloth, you can consider using landscape fabric or even newspaper to block weed growth from below, but keep in mind that weed seeds can fall onto the soil and germinate.
If the wood isn’t rot-resistant, staple heavy-duty plastic along the inside walls before adding the soil.
Adding Soil and Plants
Start with high-quality soil and choose plants that’ll work in the location you select. Plant tags show details on the care and conditions the plants need to thrive. See How to Read a Plant Tag.
Set the plants in holes and lightly fill in with soil. Keep the soil loose around the plants to allow water to reach the roots.
Good to Know
If you use container plants, break up the root ball before planting.
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The best time to water is morning, when less water evaporates in the sun. Read Watering Tips for more ideas, and check the plant tags for additional recommendations.
Raised Garden Bed Options
Consider adding a mesh cover to keep birds and rabbits away. You can build the frame with wood and PVC pipes as well as add a garden trellis next to the bed for vines and tall plants.
Good to Know
If you want to get an early start on gardening or keep things growing later in the season, cover the mesh frame with plastic to protect the plants from cooler temperatures.
What Type of Wood Do I Use?
The wood to use for a raised bed is your decision. Here are some options:
Cedar and redwood are naturally water-resistant but can be expensive and hard to find. Hemlock, fir and pine are suitable materials for raised beds but aren’t very long-lasting.
Pressure treated lumber is an option. Pressure treated lumber has been a controversial topic for many years. The purpose for chemical pressure treatment is to protect wood from rot, decay and wood-ingesting insects. Chromated copper arsenate (CCA) was the most controversial treatment and was banned for consumer use by the Environmental Protection Agency in 2003. Current treatments such as alkaline copper quaternary (ACQ) are deemed low-risk by the EPA and designated safe for use around humans, pets, plants and vegetables. Creosote-treated wood is not a good option for vegetable raised beds.
Compared to untreated wood, pressure treated lumber lasts longer and is available at a comparable cost. Some types are specifically treated for ground contact. But keep in mind that even water-based treatments such as ACQ contain the fungicide and pesticide necessary to make it effective. Here are some practices that may address concerns about using it in raised beds.
- Let the wood dry before use. It can take six months or longer for treated lumber to dry. You can then use as-is or paint or seal it.
- Line the interior sides of the bed with sheet plastic or pond liner.
- Plant edibles nearer the center of the bed, a few inches away from the wood.
Follow these guidelines and safety precautions anytime you use pressure treated lumber:
- Use fasteners and hardware labeled for treated lumber — stainless-steel or hot-dipped, galvanized screws.
- Butt lumber tightly. Pressure treated wood shrinks as it dries.
- Drill pilot holes to prevent splitting when nailing or screwing boards.
- Use wood rated for ground contact when necessary for the project.
- Wear gloves, a dust mask and eye protection when handling or cutting wood.
- Wash your hands after working with treated wood.
- Dispose of sawdust and waste according to local regulations.
- Don’t burn pressure treated wood.
- Don’t use pressure treated wood as mulch.
Read more about pressure treated lumber and wood preservatives on the EPA website: Overview of Wood Preservative Chemicals.