The Best Type Of Wood For Planter Boxes (& What To Avoid)

There are tons of good reasons to opt for a wooden planter box — perhaps you're short on gardening space or don't have suitable soil in your yard. With a planter box or raised bed, you have much more control over the growing conditions of your beloved plants. But to reap the most benefits out of a planter box, you must pick the best type of wood to build it with. Look for rot- and pest-resistant wood such as cedar or redwood.

Planter boxes come into contact with moisture often, from rain to humidity to watering sessions. Many types of wood will quickly start to split and decay when left in wet conditions so frequently, and while waterproofing a wooden planter box is an option, it's best to start with a naturally rot-resistant type of wood as a base. Cedar and redwood contain tannins, oils, and acids that help them resist moisture and decay for years. Other woods without these substances won't last as long, so they may be more trouble than they're worth.

Pests are also a reality for outdoor planter boxes. Some fungi species feed on wood and cause it to eventually rot, not to mention insects. For other projects, you can use pressure-treated wood to avoid rot and pest issues, but that isn't ideal for plants (especially edible ones) since the chemicals may leach into the soil. With cedar and redwood, there is no need to apply a special treatment — they resist fungi, insects, and other pests on their own.

Cedar is also lightweight, making it a breeze to work with, and it's durable enough to resist cracking, shrinking, or warping. There are several types of cedar to choose from, including eastern red cedar, western red cedar, and white cedar. Out of the cedars, western red cedar is the top choice for planters because it's the most durable. You can also treat a cedar planter box before using it to make it last even longer; just make sure to use a natural product.

Redwood has similar benefits to cedar: it resists decay and pest damage, is easy to work with, and is stable without a tendency to twist or warp. Redwood also has a neutral pH that won't make the soil more acidic or alkaline. Look for heartwood pieces if possible since they contain the most rot-resisting chemicals. Redwood should also be sealed to prevent cracking.

Avoid using pressure-treated wood, plywood, or particleboard, all of which often contain chemicals and glues that can leach into the soil and into your body as you garden. Recycled wood is best avoided unless you're 100% sure that it hasn't been pressure-treated. Lastly, steer away from black walnut, hickory, or black cherry, which contain a chemical called juglone that can harm plants growing nearby. If you're on a tight budget, you can use a cheaper wood without natural rot resistance such as pine. Just keep in mind that it won't last as long as cedar or redwood. Add a natural sealant, drill plenty of drainage holes, and line your raised garden beds with plastic.