Build Your Own Raised Bedscomments (16) February 24th, 2009
Raised beds solved many of the garden problems that faced me 20 years ago in our new southern California home. Among the challenges were terrible soil, a concrete-paved yard, arid growing conditions, small children, and a big, exuberant puppy. I found the raised bed solution to be a great success, and only now am I having that first set replaced with new ones.
The sizable sunny space turned out to be about 2,000 sq. ft. of concrete pavement, minus a 3-ft. planted perimeter. True, it was large enough for a decent-size garden. But also true was that what little soil existed was heavily compacted and lacked organic content.
Once before, we had been faced with difficult growing conditions. On a granite ledge with no soil in New Hampshire, my husband had built a raised bed where I grew a small salad garden. Why not design a system of raised beds that would allow me to grow vegetables year-round?
Getting more for less from a raised bed
In addition to the concrete and poor soil, there were a number of reasons raised beds seemed the perfect way to garden. First, my husband, Frank, was an accomplished carpenter and could build the boxes. Second, we could leave the concrete in place and simply break up the portions under the boxes to provide drainage.
|Dirt poor, the original subsoil (left) became black gold (right) by amending it with chicken manure, compost, and topsoil.|
Because we live in a Mediterranean-type climate with less than 10 in. of rainfall per year and almost none between April and November, we knew we would have to irrigate. Raised beds allowed us to set up an irrigation system that included a hose bib in each box. This would allow us to water each bed independently.
It didn’t take long for us to see that our raised beds had several unanticipated advantages. Our golden retriever puppy loved to race around the beds but rarely jumped into them. Our children, Josh and Jessa, could easily ride their Big Wheels around the obstacle course we had unwittingly developed for them. And neither these activities nor my gardening compacted the soil because no one ever walked on it. It remained fluffy and well aerated, allowing plant roots to grow freely.
Deciding on the design
|Redwood is the material of choice for West Coast gardens, and once you have your materials together, the beds take only about half an hour to build.|
|The 4-ft. width of the raised beds allows the author to reach the center from either side. Paths 3 ft. wide accommodate a wheelbarrow.|
The design of the beds was derived from several practical considerations. The dimensions, 4 ft. by 8 ft., were based on the fact that lumber was available in 8-ft. lengths, so it would require a minimum of cutting and no waste. I could comfortably reach only 24 in. into the beds, so a width of 4 ft. would allow access from both sides to the middle.
I also measured several of our chairs and found they all had a seat height of 16 in. to 19 in. Since we had decided to use 2x6 redwood, we could stack the boards three high and end up with a finished height of 16-1⁄2 in. (the actual width of a 2x6 is 5-1⁄2 in.). This made the edge of the box a comfortable height on which to perch and gave more than enough root run for the plants.
The boards were nailed to 4x4 corner posts that extend nearly 8 in. higher than the sides. I use bird netting during seed germination and clear plastic to warm pepper and melon seedlings. I drape these covers over the posts. The paths between the beds are 3 ft. wide to accommodate a wheelbarrow, which I use to transfer compost from its bin to the boxes.
|Two nails per board secure the boards to the post. The bottom board should be flush with the bottom of the post; the top of the post extends about 7-1/2 in. above the top board.||Stand the long boards with posts on the ground, parallel to each other and 4 ft. apart. comoplete the bed by nailing the short boards to the posts.|
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