With just a few basic tools and easily acquired materials, anyone, no matter how (un)skilled, can construct a simple raised bed garden plot out of landscape timbers found at most home improvement or garden supply stores. Because it will lift the garden plot above ground, beyond the reach of many small herbivorous creatures, a raised wooden garden bed is a simple, functional, and attractive choice for gardeners in most urban environments.
This plan provides guidelines for building a raised wood-framed garden bed using either treated or untreated lumber. This design is for an 8’x4’ wooden raised garden bed. However, the construction principles are the same for a raised garden bed of any size. Only the list of materials and lengths would need to be altered.
List of Materials for Constructing a Raised Garden Bed
- 12-8’ Landscape Timbers (rounded or square)
- 8-12” Galvanized Spikes
- 36-6” Galvanized Spikes (or 2” longer than the thickness of the landscape timbers)
- 1- 8’x4’ layer of corrugated cardboard
- 1-8’x4’ layer of Garden Mulch (wood chips, or other mulch material)
- 1-8’x4’ layer of Compost
- 1-8’x4’ layer of Topsoil
List of Tools Needed to Construct a Raised Garden Bed
- Powered Drill (NOT cordless)
- Large Hammer (two pound sledge)
- Large Drill Bit (slightly smaller diameter than the diameter of the 12” spikes)
- Small Drill Bit (slightly smaller diameter than the diameter of the small spikes)
- Large Saw (any saw that will cleanly cut through the landscape timbers)
Raised Garden Bed Assembly Instructions
- Cut four of the 8’ landscape timbers in half (creating 8-4’ sections)
- Measure the width of the landscape timbers.
- Multiply the width by 2 (if the timbers are 3” wide then 6” is the number used need for steps 4 & 5)
- Cut 2x the width of the timbers from 4 of the 4’ timbers (so if the timbers are 3” wide, cut 6” off of 4-4’ timbers)
- Cut 2x the width of the timbers from 4 of the 8’ timbers (so if the timbers are 3” wide, cut 6” off of 4-8’ timbers)
- Next find a good level spot for the garden bed and lay two 8’ timbers out and put two of the “short” 4’ timbers (with 2x the width removed) between the ends of the 8’ timbers.
- Make sure that all corners are square.
- Drill (fitted with a bit that is slightly narrower than the 12” galvanized spikes) holes at the 1/3 and 2/3 points along each of the timbers.
- Hammer 12” spikes through the holes and into the ground; keep all corners square. This layer should now be firmly anchored to the ground.
- Place a 4’ timber over each of the end pieces that have been anchored into the ground. These will lap over the ends of the bottom 8’ timbers.
- Between these (running the length of the bed) place two of the “short” 8’ timbers (with 2x the width cut off).
- Drill three holes (using the drill bit that is slightly narrower than the 6” galvanized spikes) in every corner (two on the “long” board at each corner, and one on the “short” board at each corner.
- Continue building the box in this fashion by overlapping long and short boards until there are four layers of timbers, each spiked to the layer below.
- Install a layer of corrugated cardboard/newsprint. Wet thoroughly.
- Add compost, topsoil, and garden mulch until the bed is full.
This proven method of construction is very adaptable. Gardeners should feel free to alter the dimensions and use whatever soil mixtures they deem necessary.
Glenn Kaufmann - Having moved every four years up to the age of 12, I've always been something of a restless soul ready to take on the next big thing. I ...
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