Gardening: Build your own raised bed for your garden

A couple of weeks ago, after I briefly talked about rebuilding my raised bed boxes, I had several readers ask for more details about how I built them. So, here goes.

Raised beds make gardening easier for several reasons. First, raised beds are easier to work, because they are higher off the ground. This is important if you have mobility issues that limit getting down on the ground. As they are usually filled with good-quality soil and compost, weed issues are much less of a problem than dealing with the weed seed bank in native soil. They allow you to customize soil mixes for plants like blueberries that prefer acidic soil. Lastly, they are much easier to water, especially when using drip irrigation. Boxes can be built out of cedar or Douglas fir lumber, cinder blocks, untreated timbers or even stacked chunks of concrete. Wood treated with preservatives is not recommended because the chemical can leach into the soil. Pine is not a good choice because it rots quickly. The boxes shouldn’t be wider than 4 feet so you can easily reach the center of the box.

I opted to rebuild my boxes with Douglas fir, 2-by-10-inch lumber. While cedar is more rot resistant than the Douglas fir, it is also way more expensive and beyond my budget. Enough lumber and supplies to build three 4-by-12-foot and two 4-by-14-foot boxes cost about $500. I used deck screws to screw the boxes together as they have an aggressive grip.

To start, I created an assembly line to prepare the wood. I stapled black plastic onto the boards that would face the soil to protect them from rot. I made a template out of cardboard to standardize screw placement and drilled pilot holes in the wood. To make assembly in the garden easier, I premounted the screws in the boards. To prepare the 4-foot-long box end pieces, I screwed a piece of 12-inch-long, 4-by-4 -inch post material to each end of the board to create a more durable, stable corner. Over time, freezing and thawing can loosen the screws if they aren’t reinforced.

To assemble the boxes, I had to work around some existing raised irrigation pipes that could not be moved. These first end boards had to be set and leveled just under these existing pipes. As a result, this became my leveling point for all the boxes. After setting the first end pieces, I worked my way through the rest of the boxes, screwing the side boards onto the end pieces in each box. I left 2 feet between the boxes for wheelbarrow and walking access.

Lastly, to calculate the soil I would need, I multiplied the width by length by depth of the boxes to get the cubic feet of soil needed and divided that number by 27 to get the cubic yards I ordered. The boxes were then filled with a commercial, 50-50% blend of the soil company’s “garden blend” and straight compost.