One of the first lessons I learned as a gardener is that if you don’t have high-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 soon realized that the dirt in our backyard was not viable for growing. Thick with clay, it was intersected by so many roots that it was impossible to push the shovel into the earth without hitting one.

I needed raised beds — filled with quality soil — before I could sow my first season’s plantings. I purchased a few kits made with untreated wood that were cheap and easy to assemble, and packed them with a combination of bagged soil and composted kitchen scraps.

It only took me a couple of years to regret my choice. The side planks buckled, and those resting on the ground rotted away. The rich loam inside began spilling out onto the white pebble pathways 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 with three gardening experts and spent a lot of time researching my options.

Here are the five factors they say you should consider when choosing raised-bed kits.

Materials

Kevin Espiritu, founder of the how-to site Epic Gardening, generally recommends buying metal raised beds over those made of wood.

Advertising

“When you do the calculation on longevity of metal versus wood, metal beats out wood,” he says. “And during the pandemic, the cost for wood has skyrocketed, so sometimes wood is even more expensive than metal.”

He notes that good metal beds will last more than a decade with proper care, which includes ensuring the bed doesn’t flood often or consistently sit in moisture. It also helps to line it with geotextile fabric or landscape fabric if you’re growing crops that require acidic soil, which will corrode the metal.

Size

Beds should be at least a foot tall, says Josh Singer, a community garden specialist with the Washington, D.C., Department of Parks and Recreation.

“Bigger crops, such as tomatoes and squash, need at least that much room for their roots to grow,” he says, adding that, if the bed doesn’t have a bottom, you can dig up another foot of ground below the bed to give plants space to expand.

To ensure that you can easily reach across the entire bed — and that it won’t be so long that the sides bow out — he advises keeping beds 2–4 feet wide and 4–8 feet long.

Beauty

“In urban and suburban areas, you probably only have a patio or small yard, so you’re probably going to want to like what you’re looking at out there,” says Tim Williams, operations manager of Greenstreet Gardens, a landscaping and design company. “But if pretty isn’t a factor for you, don’t worry about it. No one is going to judge you.”

Advertising

Assembly

“It’s smart to have gloves on hand,” Espiritu says. “I always assemble kits using a drill with a screwdriver bit on it — set to a low torque, so you’re not over-screwing the bolt or stripping it out — because it’s faster. And have someone with you to help with the build. It’ll just be easier.”

Ensure that your bed is on even ground because a raised bed on a slope will get unbalanced moisture distribution and may leak soil. Use a level if you want to be exact.

Cost

Last, but never least, consider your budget. A metal raised-bed kit can cost several hundred dollars, plus shipping fees if it’s not available locally. At this time of year, thought, kits may be on sale or on clearance. “But don’t wait too long, because they will become unavailable, and it will be too late to plant most things,” Williams says.

Options

Here are four raised-bed kits the experts recommend.

Vego Garden 17-inch Tall 6-in-1 Raised Garden Bed Kit. If you’ve browsed for raised-bed options on Instagram, you’ve probably seen these eye-catching beds with rounded corners. Williams is a fan. “It’s fantastic how much surface area you can get and the large soil volume for deep root systems,” he says.

The 10-piece kit with 17-inch-tall sides can be built into six configurations, both square and rectangular. It takes about 35 minutes to put together. It costs $180 at vegogarden.com.

Birdies Tall Modular Raised Bed. Australia-based Birdies has been producing corrugated raised beds for more than 13 years. Made of galvanized steel with an Aluzinc coating, the bed can be configured nine ways, both rectangular and square. It’s 29 inches tall, so you don’t have to bend over to reach your plants, Espiritu says, “which is great for gardeners who are elderly or who have accessibility issues.”

Advertising

Set aside about 45 minutes to build and install it. It’s $359 at gardeners.com.

Olle 17-inch Tall 12-in-1 Galvanized Raised Garden Bed. Singer likes this kit because of its durability and height. The panels are made of galvanized steel coated with Aluzinc, designed to reflect the sun and maintain a consistent soil temperature.

When it comes to filling it, Singer recommends a blend of 90% topsoil and 10% compost; the latter will decompose over the year. “Dump a couple of bags of compost into the bed at the start of each year to refresh the organic matter,” he says. “And since the soil compacts, you really have to till it well every year.”

The 12-piece kit of 17-inch-tall panels can be transformed into a dozen configurations, both rectangular and square. It should take about 35 minutes to assemble. The kits are on sale for $199 at ollegardens.com.

Gardener’s Supply Company Forever Raised Beds. “If you want a bed that isn’t wood but will last a long time and looks like wood, this is the way to go,” Espiritu says. Designed to look like cedar planks, these beds are made from a composite of recycled wood and plastic.

They are available in configurations of 3 by 3 feet or 3 by 6 feet, making them great for smaller backyard gardens. Expect either to take about 15 to 20 minutes to assemble. They are $229–$329 at gardeners.com.