Building Raised Beds

  • Difficulty Rating: Beginner
Building Raised Beds

In a previous Fiskars gardening article, I shared the story of the day my husband fenced off a 50 foot x 100 foot area that would be my first "real" garden.

His faith in me exceeded the reality of my gardening abilities so over time he's worked with me to make the garden more manageable. I went from frustrating days of being near tears over never-ending weed pulling to a garden that requires only about 15 minutes a week to weed. Not only is my time spent weeding greatly reduced, the soil I'm working in now is so fabulous, instead of the need to grasp a weed with both hands and dig my heels in on either side before yanking, I can pull most of them with a thumb and 2 fingers.

The cure for my gardening woes was raised beds. By confining my growing area to wood boxes measuring around 10 foot x 4 foot, the surface area I was gardening may have been greatly reduced but I saw a significant increase in my vegetable production. This is because, with raised beds, you have control over the composition of the soil that goes into them. You control the texture of it and the nutrients in it through your choice of what and how much of each soil ingredient you use.

There are many ways to build raised beds. You can use a variety of materials to create the barriers (such as cinder blocks, rocks, or wood lumber) that will confine the soil to the area you choose. Our first raised beds were old recycled tire tractors that we're gradually replacing!
There are also kits available for purchase to help you build your beds. There are kits that include prefabricated plastic walls. There are kits that include lumber cut in such a way that assembly requires only pins provided in the kit; no tools or screws are necessary. You can also purchase specialized brackets to make the job easier. While these are all great options, for those working within a the constraints of a small budget or who plan to build a lot of beds, they may not be the right option.

My husband built our first beds about 5 years ago and we've added a few new ones each year. In all he's constructed 13 beds. To keep our garden cost-effective, we use lumber and lag bolts.

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Our lumber of choice is 2 inch x 12 inch white oak. We purchase boards in 10 foot lengths from a local Mennonite saw mill which is less expensive than buying from lumber yards. White oak weathers very well so it doesn't deteriorate as quickly as some other woods.
When constructing your own beds, you have the freedom to make them as long and wide as you want. We have a variety of sizes of beds in our garden, determined by the space available in each area, but the beds I'll share today each required three 10 foot long boards. Two of the boards were left uncut. The third was cut in half to make two 5 foot long end boards.

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We purchase 5/16 inch lag bolts and a washer to go with each one. The lag bolts are 3.5 inches long.

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Two pilot holes are pre-drilled at the end of each long board, near the top and bottom of the board, 7/8 inch from the end. These pilot holes prevent the board from splitting along the grain when the screw end of the bolt passes through it. They also help prevent the lag bolts from breaking.

After reading the next step, your basic math calculations may tell you that drilling the pilot holes 7/8 inch in from the end of the long boards will not land the holes in the center of a 2 inch thick piece of lumber. The truth is the 2 inch thick lumber you purchase is actually only 1 3/4 inch thick after it's been run through a planer to smooth its surfaces. So 7/8 inch it is!

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The boards are then aligned by butting the end of the side boards up to the pilot holes on the long boards. The pilot holes should rest over the center of the end of the short boards. Holes are then pre-drilled into the short boards using the earlier drilled pilot holes in the long boards as a guide.

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The lag bolts are inserted into the pilot holes and tightened down using a socket wrench. The bolts are tightened down just until flush with surface of the board because white oak is so hard and dense, too much torque on the bolts can cause them to break.

At this point, you can attach a wire mesh material to the bottom of the bed to prevent moles from finding their way into your beds and wreaking havoc.

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When researching building raised beds, you will find there are a lot of opinions on the best way to build them. It is common to read that you should not attach the boards by running a screw straight through the side board and into the end grain of the short board, as we do, because the screws will not hold over time. Another belief is the corners of the bed are not structurally sound. Many people use corner brackets to hold the boards together or run another short length of board vertically in each corner, screwing the side and end boards into these rather than into one another. This photo shows the corner of one of our beds that is 5 years old. The boards still fit together as snugly and the integrity of the corners is as sound as the day it was built. The white oak boards have not warped or decomposed and, while using brackets or wood braces work too, this method of connecting the boards has worked fine for us.

Once completed, we filled out new beds with partially composted cow manure. Overfilling them slightly allows for continued decomposition over the winter. Next spring, when I'm ready to plant my tomato plants in these new beds, the soil level should be perfect!

Our total cost, per bed, is a little over $100. Considering the number of beds we have and the large size of them, building them ourselves using lumber from a sawmill has resulted in a significant savings over purchasing a raised bed kit or purchasing lumber from a lumber yard. When researching raised bed options that fill your own needs, if your final decision is to make them yourself, consider trying to locate a local sawmill from which to purchase your materials.