Build A Raised Garden Bed

Just get ’er done.

Projects are like this sometimes. They don’t light your fire, but they’re necessary. Such was the case with this raised garden bed.

My wife Jane is a gardener, and when she asked that I replace our old raised garden beds, I didn’t even roll my eyes. I had to admit that the beds, made of nailed-together treated 2x10s that were falling apart, had become an eyesore.

I agreed to build two new beds, but I vowed to keep them simple — no flying buttresses to support Big Boy tomatoes. This approach got the job done but didn’t tax me, and I was proud of the results at the end of the day.

BTW, you might wonder why we would bother building raised garden beds rather than planting directly in the ground (and saving ourselves the work and expense). The reason is that raised beds elevate your gardening game because:

• They look good, giving gardens a tidy appearance.
• There’s less stooping when planting, weeding and harvesting.
• Some styles enable you to sit on the edge as you work.
• You can control soil quality, mixing exactly the types of soils and materials that you want.

Below are the tools, materials and instructions you need for building this kind of raised bed. You can build yours whatever size you wish; these are 7x3 ½-ft. and 4x3 ½-ft. and fit nicely along the side of the house.

Tools Needed:

• Circular saw
• Shovel
• Wheelbarrow
• Hoe
• Framing square
• 3- or 4-ft. level
• Drill/driver
• Sledgehammer
• Speed square
• Hacksaw to cut rebar (optional)

Supplies:

• 4x4 cedar timbers - Typically sold in 8-ft. lengths. Cedar (or redwood) timbers look good and weather well; you don’t have to apply finish to protect the wood. Pressure-treated wood also works and is cheaper, but it doesn’t look as good. Buy enough for two to three layers, and check that each timber has straight edges and is mostly clear of knots on at least one side.
• ½-in. rebar - Great for securing the foundation timbers to the ground, especially when the bed is on a slight slope or uneven terrain. Rebar is sold in 18- to 24-in. lengths; 18-in. pieces are fine for making sure 4x4 timbers stay put.
• 6-in. landscape screws - Timberlok and Timbrex brands, for example, for fastening the sides together
• Pea gravel and sand - For drainage under the walls and prevention of rot in foundation timbers
• Topsoil/compost mix 

Building Instructions

1. Determine the dimensions. Make the bed no more than 4 ft. wide or you’ll have a hard time reaching plants in the middle. Each side should be constructed of only one timber per layer, so make the dimensions no more than 8 ft. per side or buy longer timbers.

2. Cut the timbers. When determining how long to make the timbers, remember that they will butt end-to-side. You’ll need to subtract 3 ½ in. (the true width of a 4x4 timber) from the length of each side. Using a circular saw, cut all timbers according to your specific dimensions, four timbers per layer.

3. Outline the bed. Lay out the first layer of timbers at the work site. Butt the end of each timber to the side of the next timber, working clockwise. Use a shovel to cut into the turf and mark the outline on both sides of the timbers.

4. Dig. Remove the timbers and dig out the turf and dirt within the outline to create a trench for each board. The trench should be 2 to 3 in. deep (or deeper if you are on a slope). Reuse the dirt in the bed and the turf for patching spots in your lawn.

5. Spread gravel. Put 1 to 2 in. of gravel in the trench and spread it evenly with a hoe. If the ground is normally porous, you can substitute sand for gravel.

6. Bore holes. Use a drill/driver with a ½-in. spade bit to drill holes through the four foundation timbers about every 2 ft. Rebar will go through these holes and into the ground.

7. Set the first layer. Arrange timbers in the trenches as you did before, with the holes vertical. Use the level, framing square and speed square to ensure that this layer of timbers is level and the bed is square.

8. Secure with rebar. Use a sledgehammer to drive a length of rebar through the holes and at least 1 ft. into the ground. Make sure each piece of rebar is flush with the top of the board. Continue to check for level as you pound the rebar.

9. Build the walls. Arrange the next layer of timbers on the foundation, but this time work counterclockwise. This way the timbers will overlap at the corners in the opposite direction from the first layer, creating a lapped pattern. If you choose to add more layers, continue to alternate directions.

10. Fasten the timbers. Use a drill/driver to drive landscape screws through the top course and into the timber beneath. Put two screws at each corner and two in each side.

11. Drill weep holes. Use an extended ½-in. spade bit to drill weep holes, two in each long side of the bed and one in each short side. Drill from the outside so that tear-out doesn’t show, and angle the bit upward so water will flow out.

12. Fill the bed. Shovel in 3 in. of gravel to create the base of the bed; then add topsoil. Fill to within 2 to 3 in. of the top, tamping lightly as you fill.

Option: Install a cap railing of 2x6s secured to the top layer of timbers with 3-in. decking screws.