Above-ground gardening

Raised beds put drainage, accessibility within reach

There are many reasons for using raised garden beds rather than traditional in-ground beds. Avoiding underground utility lines is one popular reason. Adding a bit of height for easier accessibility is another. Better drainage (especially in heavy clay soils) is yet another, and, as a bonus, the soil in a raised bed will warm up just a little bit sooner in the spring.

I’m seeing an increasing number of elevated beds, too. “Elevated” goes a foot or two beyond “raised” to put the garden about waist-high for a standing adult and within easy reach for a seated adult. They’re popular at public gardens and healthcare facilities. Imagine being a wheelchair-powered person in a retirement center and feeling sad because you think your gardening days are behind you. With elevated beds and other work-arounds, they don’t have to be. Some elevated beds are made of stone or brick and serve as part of the landscape, but others are actually portable.

Yet another reason for using raised beds is that they can look really cool. These days, we have some great choices – tiered, flat, square, white, robin’s egg blue and more variations. One online retailer has elevated beds ranging from the utilitarian planter box to fashionable “patio gardens” in several colors. For raised beds, it carries several cedar choices and one made of a recycled wood-plastic composite that is said to resist rotting and splitting. The big-box retailers have plenty of choices, too – certainly more than they did a decade or so ago – but many of these are not sold in stores and must be ordered.

Before you subject yourself to shopping overwhelm, here are a few basic points to consider.

Keep the size within reach. Raised beds should generally be no wider than three feet – four, tops. You want to be able to easily reach all parts of the bed without stepping into it. A raised bed should also be at least a foot high. For gardeners who have trouble bending and stooping or are just tired of doing so, you’d want it two or three feet high. (At what height does a raised bed become an elevated bed? Doesn’t matter – as long as it works for you.) If you want to try the increasingly popular square-foot gardening, you’ll want a 3-by-3 or 4-by-4.

Know your materials. Treated lumber can leach heavy metals like chromium and arsenic, and railroad ties can leach creosote. Cedar looks great, smells great and is naturally resistant to rot and insect damage, but the elements will take their toll in time. Other choices, which may be more expensive but last longer, include stone, cinder blocks, bricks and composite/recycled materials. Again, I’d stay away from railroad ties. With wood, you can also line your raised beds with plastic to eliminate or minimize contact with the soil.

Prepare the site properly. You can’t just plop a raised bed anywhere, dump in some soil and start planting. You have to kill or remove existing turf first. Deeper beds will need layers of drainage material such as crushed rock, pea gravel or sand at the bottom to allow water to drain freely.

About that drainage: Make sure you incorporate manure, compost or other organic materials, as well as vermiculite or perlite, for well-aerated and well-drained soil. The best soil in the nicest beds won’t do any good if air and water can’t get through.

Purdue Publication HO-200: Container and Raised Bed Gardening is worth checking out, especially if you’re working with limited space. Allen County Extension has a publication, ACH 203: Raised Bed Gardens, with more details on site preparation, including how to calculate how much soil you’ll need.

Personally, I would go to a locally owned and operated garden center or landscaping supply center. Tell the folks there what you’d like to plant and the dimensions of your raised beds. They generally have a variety of soil mixes available and can make good recommendations. They might even help you with the math.

I have had pretty good luck with growing flowers and vegetables in raised beds for years. The biggest problem now is canine interference, but gardening with delinquent dogs is a topic for another column.

First appeared in the May 2016 issue of Fort Wayne Magazine.

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