Want to know the best wood for raised garden beds? Raised beds are garden containers, commonly made from wood, and the type of wood we use will determine how long-lasting, safe, and sustainable they are. Show
If you are looking for designs, I have free plans for building raised garden beds here . Choosing Wood for Raised BedsYou’ve got perfect soil, a level yard, consistent rainfall, and everything grows beautifully, right? Ok. No. Every garden has challenges and raised beds can resolve many of them. Bad soil, a sloping yard, and tree roots are all reasons to grow in raised garden boxes. A raised growing space is also better for back and knee problems. But what kind of wood should you use? Are some types of wood harmful for the garden? Wood is a popular choice for building plant boxes because it’s fairly inexpensive, readily available, and lasts quite a few years. But you do have to choose carefully to avoid contaminating the soil and ensure your choice is eco-friendly source, affordable, and long-lasting. So, unless you live in termite territory, it’s time to go wood shopping. Contents
What is the Best Wood for Raised Garden Beds?Here are the key traits to look for, then we’ll explore the details.
For me, locally-sourced, FSC-certified, untreated, rot-resistant wood makes the most sense. But it is not always possible to check all these boxes. I currently use 1-inch untreated pine boards because they are readily available in my area. The wood gets a lovely, rustic barn board patina but lasts for many years in my Canadian climate. I also use some pressure-treated wood for various garden structures including large raised beds. The wood that people worry about leaching ‘chemicals’ into the soil is CCA (Chromated copper arsenate) pressure-treated wood or old railway ties. This type of treated wood was banned years ago for household use. You can read more about it below. Keep in mind that wood selections vary greatly by region. I admit the suggestions (below) are quite idealistic, but why not do what’s best for the health of your garden and the environment if you can? What to Consider1Local & SustainableThe best choice (and often the lowest cost) is locally-sourced wood coming from sustainably-managed tree farms (as opposed to decimating old-growth forest by clear-cutting). 2FSC CertifiedIf you can, use wood with FSC (Forest Stewardship Council) certification. The FSC is an international, not for-profit organization that promotes the responsible management of forests. 3Safety ConsiderationsTreated LumberIf you want to use treated lumber, do your homework first so you’re certain it’s safe for your food garden. Safety standards and regulations vary by region. I notice some manufacturers now specifically mention if they consider their treated wood safe for vegetable gardens, where they used to just mention use for fence posts and decks. It’s up to you to do some research to decide if you trust them. What goes in your soil goes in the water, plants, and wildlife, so it’s important to be careful. Some Current Wood Treatment Methods:
TIP: To be cautious, some gardeners line their treated wood beds with a protective layer of plastic to form a barrier between the wood and soil. Again, you will need to research the plastic to ensure it is food safe and consider the effects of condensation forming between the plastic and the wood. 4Durability and Rot-ResistanceHow long any wood lasts will depend entirely on the type of wood and local conditions. My current raised beds are made from 1-inch untreated pine and last approximately 10 years. But I also live somewhere where the rain is moderate and drainage is very good. If your raised beds will be exposed to a lot of moisture, wood like pine may only last a few years. Wood borers like termites are also a possible concern. Other naturally rot-resistant woods (listed below) will last even longer. Should raised beds be sealed (water-tight)?Opinions are mixed on whether wooden raised garden beds should be sealed with caulking or sealant to try and make them water tight. I do not do this, preferring to allow excess water to drain out more readily. Wood OptionsCheck before you buy to be sure the wood meets your criteria. Here’s a few popular ones: Naturally Rot-Resistant and Long-Lasting
Dense Woods
Check your local lumber yard for more ideas. Wood to AvoidDo your research first to confirm you are comfortable with the exact product you are using. Be Cautious
Do not use CCA (Chromated copper arsenate) pressure-treated wood or old railway ties. This method of preserving wood was voluntarily discontinued in the production of residential woods in the United States (2003) and Canada (2004), but it is still used for industrial purposes. The concern is arsenate leaching into the soil and uptake by plants. As thrifty gardeners, we like to repurpose wood that seems to be in good condition, but this is not an option with old, treated wood. Read more:
Wood Alternatives for Building Raised BedsAs with any building materials, you must do your own research to make sure the choices you make are safe, eco-friendly, sustainable, and right for your situation. These are ideas to research further, not recommendations.
AvoidCinder Blocks Versus Concrete BlocksCinder blocks (popular many years ago) are made from fly ash and contain heavy metals. These are not considered safe for gardens. Concrete blocks are generally considered fine but always check what the product is made from to be sure. These all have safety concerns:
ResourcesFree Tip SheetEmpress of Dirt Best Wood Options For Raised Garden Beds Save to your device and/or print it. My Raised Bed With Privacy WallsAlso see DIY Raised Garden Bed With Built-In Privacy Wall. Frugal Building Tip
I like to use 8-foot lengths to create easy-to-assemble 4×8-foot boxes but also keep in mind what fits your body size for easy reaching. Free Building Plans
Save On Soil
Recommended Book
As always, when making garden decisions, consider the effect on the soil, water, air, and wildlife. ~Melissa the Empress of Dirt ♛ What is the cheapest wood for raised garden beds?The least expensive and most readily available wood for a raised garden bed is pine. It's ideal for short-term gardens at rental properties or temporary gardens that last for about 3 to 4 years. The short life of pine is because it has a low level of tannins, so it isn't protected from rot, decay, and pests.
What is the best material for a raised garden bed?Build your raised bed with a decay-resistant type of wood, such as cedar, black cherry, oak (bur, chestnut, post, white), black locust, Osage orange, or redwood. (Source: USDA Forest Products Lab) Use a non-wood material such as stones, concrete blocks, bricks, or synthetic lumber.
Should I treat the wood for a raised garden bed?Sealing wood garden beds can help extend their lifespan many years beyond unsealed wood. Applying a sealer will protect the wood from moisture intrusion, mold, and decay. However, you don't want to use just any wood sealer on your garden beds!
How thick should the wood be for a raised garden bed?Make your raised bed from lumber that is either 1-inch or 2-inches thick; a piece of lumber that is 2 inches thick will withstand more wear than a piece of lumber that is 1 inch thick; it will also be more expensive. Standard widths of lumber are 2-, 4-, 6-, 8-, 10-, 12-inches.
|