Tips for choosing raised beds for your garden

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One of the first lessons I learned as a gardener is that if you don’t have quality soil, the greenest thumb in the world isn’t going to save your plants. When we moved into our home half a dozen years ago, I quickly realized that the dirt in our backyard was not suitable for growing. It was thick with clay and cut through by so many roots that it was impossible to drive the shovel into the earth without hitting one.

I needed raised beds to fill with garden soil before sowing my first season’s plantings. I bought some bare wood kits—they were cheap and easy to put together—and packed them with a combination of bagged soil and composted kitchen scraps.

It only took me a few years to regret my choice. The side planks buckled and those on the floor rotted. The rich clay inside began to spill onto the white pebble paths around the beds, an eyesore and a waste. This spring I ripped them out and replaced them with a trio of new raised beds and an herb garden on wheels, but first I spoke to three gardening experts and spent a lot of time researching my options.

Here are the five factors to consider when choosing raised bed kits.

Materials. Kevin Espiritu, founder of Epic Gardening, generally recommends buying metal raised beds over wooden raised beds. “If you calculate the longevity of metal versus wood, metal beats wood,” he says. “And during the pandemic, the cost of wood has skyrocketed to the point where wood is sometimes even more expensive than metal.” He notes that with proper care, good metal beds last more than a decade, which includes not flooding the bed often or sits constantly in moisture. And line it with geotextile fabric or landscape fabric if you’re growing crops that need acidic soil that will corrode the metal.

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Size. Beds should be at least a foot high, says Josh Singer, a community garden specialist at the DC Department of Parks and Recreation. “Taller plants like tomatoes and squash need at least that much space for their roots to grow,” he says, adding that you can even dig up another foot of soil under the bed to give the plants room to grow. So that you can reach across the entire bed comfortably — and so that it doesn’t get so long that the sides sag — he recommends keeping beds two to four feet wide and four to eight feet long.

Beauty. “In urban and suburban areas, you probably only have a patio or small garden, so you probably want to like what you see out there,” says Tim Williams, operations manager of Greenstreet Gardens, a landscape architect design firm. “But if pretty isn’t a factor for you, don’t worry about it. Nobody will judge you.”

Assembly. “It’s wise to have gloves on hand,” says Espiritu. “I always assemble kits using a drill with a screwdriver bit – set on a low torque so you don’t over-tighten or back out the screw – because it’s faster. And have someone with you to help set it up. It’ll just be easier.” Don’t forget to make sure your bed is on level ground, as a raised bed on a slope will get an imbalance in moisture and soil can leak out. (Have a level handy if you don’t feel comfortable staring at it.)

Costs. Finally, consider your budget. A metal raised bed kit can cost several hundred dollars plus shipping if not available locally. However, the good news is that there are many kits in the DC area for sale or clearance this time of year. “But don’t wait too long because they won’t be available anymore and it will be too late to plant most things,” says Williams.

Here are four raised bed kits that experts recommend.

The Vego Garden 17″ Six-in-One Modular Metal Raised Bed. If you’ve searched for raised bed options on Instagram, you’ve probably seen these eye-catching rounded-corner beds. Williams is a fan. “It’s amazing how much surface area you can get and the volume of soil for deep root systems,” he says. The 10-piece kit with 17″ tall sides can be installed in six configurations, both square and rectangular, including 2 by 2 feet and 5 by 3½ feet. Assembling takes about 35 minutes. When installing the panels in this kit and others, ensure the top and bottom are aligned; just rotate the panel if not.

The tall modular raised bed from Birdies. Australian company Birdies, the OG of corrugated raised beds, have been producing them for more than 13 years. The bed is made of galvanized steel with an Aluzinc coating and can be installed in nine configurations, rectangular and square, such as 40 x 24 inches and 66 x 40 inches. It’s 29 inches tall, so you don’t have to bend down to reach your plants, says Espiritu, “which is great for gardeners who are elderly or have accessibility issues.” Plan to set up and install around 45 minutes one.

Olle’s Galvanized 17″ 12-in-1 Raised Bed. The panels are made of galvanized steel and coated with Aluzinc to reflect the sun and maintain a constant floor temperature. The 12-piece kit with 17″ high panels can be converted into a dozen configurations, both rectangular and square, including 80″ x 40″ and 44″ x 24″; Assembly should take about 35 minutes. Singer likes this kit for its durability and height. For filling, he recommends a mixture of 90 percent topsoil and 10 percent compost; the latter decomposes over the year. “Put a few bags of compost in the bed at the beginning of each year to refresh the organic matter,” he says. “And since the soil is compacting, you really have to till it well every year.”

Raised beds forever. “If you want a bed that isn’t made of wood but will last and look like wood, this is the way to go,” says Espiritu. These beds look like they’re built from cedar planks and are made from a composite of recycled wood and plastic. They are available in 3 by 3 foot or 3 by 6 foot configurations, making them ideal for smaller backyard gardens. Expect assembly to take around 15 to 20 minutes.

Martell is a writer from Silver Spring, Md. His website is nevinmartell.com. Keep finding him Twitter and Instagram: @nevinmartell.

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