Gardening Q&A: Alternative Raised Bed Building Material

The Gardener

Q.The south side of my house gets the most sun. I want to install raised beds along the lattice fence that borders my property there, but since the space is narrow I'd like curvy beds instead of straight ones. Do you have any good ideas for what materials I can use other than the traditional wood plank? ~Faith Wimberly

Even though most raised beds are rectangular, there is definitely no rule that they need to be constructed that way. Curving the beds will allow you to squeeze more into a small space and prevent your side yard from looking like a bowling lane. When building the beds, try not to make them more than 3- to 4-feet across at their widest point. Any wider and it becomes difficult to reach the plants growing in the middle without stepping into the bed. Stone and brick are two great options for building curved raised beds, but they can be pricey. Here are a few inexpensive material ideas:

Curved Path

Perhaps the easiest option is to forgo the idea of enclosing the beds and instead simply make a curving pathway around low berms of soil. Use flexible steel edging (not the flimsy plastic edging) to form a barrier between the path and the beds. Gravel looks especially nice in pathways. Just be sure to buy crushed gravel, which compacts easily and tends to stay put, instead of pea gravel, which has rounded edges and rolls into the surrounding beds. I also love the way hazelnut shells look in pathways. The shells breakdown very slowly--you'll only need to refresh them every three or four years--and they turn a pretty weathered grey color as they age. Wood chips also look nice and sometimes you can score them for free by calling a local arborist and asking them to dump a load of chips at your house.

Broken Concrete

Recycled concrete, which is also sometimes called Urbanite, is the perfect raised bed material because it is readily available, free, and it stacks well. Plus, you can easily make curved beds with it. I've seen older recycled concrete walls covered with moss that look especially cool. Keep your eyes peeled for stacks of recycled concrete on the side of the road or check out the free section on CraigsList.

Straw Wattles

These mesh tubes are filled with straw and are traditionally used to prevent erosion. I spotted them used as a raised bed at the San Francisco Flower & Garden Show a few years ago. The wattles will last for a couple of seasons before they need to be replaced, so they are a great temporary option if you want to save your pennies for a more expensive, permanent material. Wattles are typically sold in 25-foot lengths and you can find them at construction supply stores, hardware stores, and online.

Tree Trimmings

For a more rustic look, try edging a bed with tree trimmings. I got this idea at The Garden for the Environment in San Francsico and used it in my own side yard last summer when I created a woodland garden. We gathered fallen branches after a windstorm, snagged some sticks from free wood piles, and used tree trimmings. Simply stack the branches together and fill in the space behind them with soil. We planted strawberries in the spaces between the sticks and it looked super cute. You can simply replace the branches with new ones as they decompose.

Terracotta Drain Pipes

Round terracotta drain pipes often turn up at re-use stores and they make an unexpected edging for a raised bed. I've seen them used in several gardens and people often plant herbs, heads of lettuce, or annual flowers in the openings of the pipes.

Willi Galloway writes The Gardener column. She lives in Portland, Oregon and writes about her kitchen garden on her blog DigginFood. Her first book Grow. Cook. Eat. A Food-Lovers Guide To Kitchen Gardening will be published in January 2012.

(Images.1. Willi Galloway 2. Middlebrook Gardens 3. All other images by Willi Galloway)