Raised bed gardening: Try it, you’ll like it
A raised bed garden by definition is simply one that is elevated off the ground. The bed can be solid to the ground and constructed with sides made of wood, brick, or other materials. The bed can simply be a berm with no permanent edges. Or, the bed can be completely elevated off the ground so that a chair can be placed under it. How you design your raised bed garden depends on your available resources, where you are putting it, and how you intend to use it.
One of the primary reasons that people choose to have a raised bed garden is to have improved soil. Much of Delaware County has hard clay soils. This is especially true in new housing developments when topsoil is removed and replaced with the clay dug out for the foundation. Also, a raised bed garden is desirable if a garden is being located on a site, such as an abandoned city lot, where the soil may be contaminated. Bill Dawson, Growing to Green Program Coordinator for the Franklin Park Conservatory, recommends in these instances that for complete safety you replace at least 18” of soil to let the roots thrive but not grow into the native soil.
Typically, a raised bed garden has a permanent border. Jim White, a Delaware County Master Gardener intern, recently built three raised beds in his yard. Two are enclosed in wood frames, and the third is constructed from bricks. He lined the bottom of each bed with a weed mat and then used premium organic garden soil from a local supplier to fill the frames.
Everyone I talked with recommended that you limit the width of a raised bed garden to about 4 feet, so you can reach to the middle of the garden from either side without standing on the bed and compressing the soil. The length of the garden can vary and depends on the space you are filling and the materials you have available.
Some of the benefits you get from raised beds include much better drainage than you have in native clay soils. They also warm up earlier in the spring, allowing you to extend the growing season. Jim White has had a garden in his backyard for many years, but he says that by converting it to raised beds his garden is better than ever. This is in direct contrast to the frustration that many local growers without raised beds have experienced due to the cold, wet spring weather. However, since these beds do have better drainage, it is necessary to water them thoroughly to avoid shallow root systems. Liz Coverdale, horticulturist at the Franklin Park Conservatory, reminds us that we don’t want “wimpy plants” that will not stand up during the hot days of summer.
Raised beds are ideal for people with limited physical abilities. Sarah Ritchea, of the Heritage Health Day Centers, coordinates a program at their facility on Dublin-Granville Road in Columbus, mainly for older adults. Program members have the option to have their own small individual raised vegetable garden. They get to choose what to plant. Then they maintain the garden on their own, or with assistance as needed. Sarah says that gardening is one of the more popular activities at the center. It’s therapeutic, and “they like to get their hands dirty.” Frequently it brings back fond memories. Raised beds that are solid to the ground are preferred by Sarah for vegetable gardening, even for people confined to wheelchairs. Raised gardens that are constructed on legs so that a chair can go under them have more limited use, as the beds are shallower and dry out more quickly, so vegetables cannot develop strong deep roots.
According to our contacts, despite the time and expense of properly installing raised beds, the benefits far outweigh the costs. They are an excellent alternative when there is a drainage issue. They also allow you to customize the soil so plants, such as blueberries, which require acidic soil, can thrive in your garden. The growing season is longer as the soil is warmer, and it is easier to work, since it is higher up and not compacted by walking. Raised beds that are solid to the ground are the most versatile and the easiest to maintain. You can hire a landscaping firm to build a bed or do it yourself. More information can be found online at Ohioline.edu in The Ohio State University Fact Sheet HYG—1641–92. Resources are also available at your local nursery, in a bookstore or your local library. Or you can contact the Delaware County Master Gardener Helpline (740–833-2030) weekdays for help in getting started.
Nancy F. Traub is an OSU Extension Delaware County Master Gardener Volunteer.