Building Raised Garden Beds

Above Ground or Ground Contact? That is the Big Question

By Belinda Remley

Whether taking on a project themselves or hiring professional contractors to handle the job, many consumers have slipped from the realm of uninformed to inquiring, self-educated project owners. Educational tools that are readily available online have led consumers to learn how to fix minor issues, know when those issues are too big to tackle and, most importantly perhaps, be able to recognize the difference between those two types of projects.

Whether a DIYer or an outsourcer, the average consumer takes the time in advance to know and understand what materials are available for their projects. According to a recent study, just over half of DIYers and most Pros spend any time researching pressure-treated wood prior to purchase. Knowing that consumers are seeking knowledge, dealers and retailers have the unique opportunity to aid in consumer education by recommending the right material for the job.

As it has been for decades, beautiful, natural preserved wood is the material of choice for many outdoor projects. Professionals and do-it-yourselfers agree nearly 60 percent of projects built by backyard contractors are created using preserved wood. The most popular of those projects is decks, but consumers and contractors also build smaller, less involved projects such as picnic tables, benches, and raised bed gardens.

Do-it-yourselfer Andy Nash agrees.

More than ten years ago as a novice weekend warrior, he chose to use preserved wood to build his raised bed gardens. “I did some research, found a garden plan online, and decided that I would attempt to build a raised bed. By the time we moved into our next house, I felt very confident when I built my second set of gardens. It just took a few boards of Wolmanized® Outdoor® Wood (2x6s and 4x4s), screws, and a few tools that I already had on hand.” Andy said he built two raised bed gardens in just a few hours. The good thing, he adds, is that the planter beds can be used year after year because they are built using Ground Contact preserved wood.

Andy’s research helped him create a successful project that will be enjoyed by his family for many years. Do-It-Yourselfers like Andy and professional contractors know that research and preparation before building can mean a finished product with which everyone will be happy.

“Knowing what kind of wood to use in an outdoor project is crucial – especially before you head to the lumber yard,” says Matt Roughen, Director of Marketing for Arxada Wood Protection, “A little bit of homework can save a lot of time and hassle down the road.”

Matt says, “Most people like the look and feel of real wood. Using wood brings a natural, beautiful aesthetic to your outdoor projects. Making sure your wood is treated properly ensures that your project will last a long time with only minor maintenance.”

Arxada has free raised garden bed plans available on their website.

What makes wood the ideal choice for your project?

Wood comes from an abundant natural resource that is grown on managed forestlands and is easily and quickly replenished. It has excellent workability in all aspects of construction and, when preserved and used properly, can be designed to create outdoor living spaces that bring the comfort of inside to the outside. It is a durable and cost-effective structural material.

Wood is easy to use, lightweight and adaptable to be modified on the job site. It is readily available from local dealers with no need for special order for your ideal color; as it can be painted or stained to create your desired look. Wood can be used year-round in any climate and can be maintained and repaired by a do-it-yourselfer. Wood’s strength-to-weight ratio is excellent and it is resistant to breaking and cracking.

Why should you use treated wood?

“For decades we in the treating industry have innovated products that enhance and extend the life of wood,” explains Matt. “Our preservative, called Wolman® E Copper Azole, is used in a pressure treatment process that infuses the preservative into and throughout the wood. The preservative helps the wood last longer by making it resistant to termites and fungal decay.”

During his research, do-it-yourselfer Andy explains that he was ready to make his purchase when he pulled up at the lumberyard. “I did my research and was able to confirm my plans with the knowledgeable professional in the store. I learned that since my wood would remain in contact with the soil and constantly be wet, I should use Ground Contact treated wood. Even with that harsh exposure my raised beds should last for years.”

Like Andy, contractors and do-it-yourselfers cannot arbitrarily choose what preserved wood to install. According to Jay Hilsenbeck, Head of Product Management for Arxada, choosing the right wood for its intended use is imperative for a finished project to last.

Jay explains that consumers can either purchase Above Ground or Ground Contact preserved wood for their project. “This decision rests on the severity of the exposure conditions of the wood during its service. Ground Contact preserved wood is treated to a higher retention level than Above Ground,” explains Jay. “That simply means there is more preservative in Ground Contact preserved wood to offer necessary protection for more demanding end uses like raised beds and structural components of decks.”

What are the rules?

Guidelines say that Above Ground preserved wood is intended for the parts of a project that are at least 6 inches above the ground, where the wood dries easily, and where it is well ventilated around all the boards. While Ground Contact preserved wood is versatile enough to be used in almost any application, it must be used in applications where the wood:

-Will come in contact with or be within 6-inches of the ground or fresh water

-Is critical to the structure and difficult to repair or replace

-Is in certain physically Above Ground uses exposed to harsher conditions such as prolonged contact with soil, vegetation or sprinklers

“As an example, deck boards that are not subject to prolonged wetting from sprinklers and have good air flow around them can be treated to Above Ground retentions,” Jay further explains. “Decking understructure such as posts, joists, and ledger boards should be treated to Ground Contact retentions.”


And when the work is finished?

Matt says that once your backyard project is complete, you can begin enjoying it immediately. “Just like common car maintenance such as changing the oil and checking the tire pressure is necessary, some maintenance to prolong the beauty of your deck can be necessary,” Matt adds. “Homeowners can easily and inexpensively perform maintenance on their decks or other backyard projects. By cleaning and applying a surface water repellent every couple of years your project will continue to look beautiful.

“Additionally, unlike other materials used in backyard projects, your treated wood deck, raised bed, or other project can be enhanced by changing the color. As easy as applying a coat of stain, you can update the appearance of your project, enabling you to keep up with the latest trends.”

Preserved wood remains the most versatile, affordable, easily accessed building material for contractors and do-it-yourselfers. As long as you familiarize yourself with the rules beforehand and choose the right wood for your application, your project will be around for your enjoyment for a long time.

For additional information, please visit

About the Author

Belinda Remley has been promoting the use of wood products – especially treated wood – for more than 25 years.

Hot Product

Trex® Seal™ Sub-Ledger Tape
Trex® Seal™ Sub-Ledger Tape

Waterproofing the ledger board is a critical step in preventing moisture damage and ensuring the structural integrity of a deck over time. To fully protect this essential component, the makers of Trex® Seal™ Ledger Tape have introduced a new butyl tape engineered specifically for use beneath the ledger board. Measuring 22 inches wide, Trex® Seal™ […]