Growing fruits, vegetables, herbs, and flowers in raised garden beds offers many advantages over traditional in-ground gardening. The added height makes tending to plants easier on the back without having to bend over or kneel as much. Raised beds also provide excellent drainage while allowing you to have greater control over the soil quality. But the key to successful raised bed gardening lies in choosing the right material to build your frames and boxes.
When it comes to wood for raised beds, not all types are created equal. The best woods are naturally rot-resistant without any chemical treatments. Pressure-treated lumber may leach toxic compounds like copper, chromium and arsenic into the soil – definitely not something you want around edible plants! This year, skip the pressure-treated timber and go with a wood that will stand the test of time without compromising your vegetation or health.
Why Choosing the Right Wood Matters for Raised Beds
The wood you select for your raised bed frames impacts a number of factors:
- Durability and lifespan – Choose a rot-resistant wood that can withstand exposure to moisture and pests.
- Resistance to rot, decay, and insect damage – Some woods have natural compounds that make them unappetizing to insects and fungi.
- Food safety – Avoid chemicals leaching into the soil from treated lumber.
That’s why smart raised bed builders look beyond cost and availability when picking wood. Consider the long-term performance as well as the safety for you and your vegetables.
The Drawbacks of Using Treated Lumber
It used to be commonplace to build raised beds from pressure-treated pine, which is pine lumber infused with chemical preservatives. The chemicals used include pesticides and fungicides along with wood stabilizers and water repellents. These help protect the wood from rot, fungal decay and insects. The problem is, these same chemicals could leach out of the wood and contaminate the soil as well as anything you grow.
Copper, chromium and arsenic comprise some of the concerning chemicals used to treat lumber. These toxic compounds can accumulate in plants as well as pose risks to people handling treated wood. For these reasons, avoiding treated lumber is highly recommended for any structure used to grow edible plants.
Key Factors in Selecting the Best Wood
Here are some of the top considerations when researching which wood to use for your new raised beds:
- Decay and rot resistance – Choose woods with natural durability and moisture resistance.
- Strength and durability – Opt for sturdy woods that can withstand weathering without warping.
- Cost and availability – Balance your budget with accessibility.
- Local climate conditions – Factor in humidity, rainfall and other environmental factors.
- Natural vs treated – Go for untreated, non-toxic woods to avoid chemicals.
Keeping those key criteria in mind will help guide you to the ideal timber for your upcoming raised bed projects.
The Case for Using Cedar Wood
When weighing all the factors, cedar emerges as the best wood for DIY raised garden beds. Here’s why cedar is a superior choice:
- Naturally rot-resistant – Heartwood contains compounds that resist decay.
- Repels insects naturally – Thujone deters pests like termites.
- Very durable and long-lasting – Can last over a decade with proper care.
- No chemicals to leach – Untreated cedar is non-toxic.
- Popular choice amongst home gardeners – Time tested and widely available.
Both Western red cedar and Eastern red cedar offer excellent rot and insect resistance. Key is finding high quality, 100% untreated cedar boards. Let’s explore some shopping tips.
Sourcing High Quality Cedar
When buying cedar, you’ll want heartwood which is the inner reddish-brown core. Avoid sapwood which is the light outer portion of the log. Heartwood contains more decay-resisting oils. Cedar with tight, vertical grain is best as it shrinks and swells less with changes in moisture.
Many home improvement stores carry cedar in forms like:
- Cedar boards in 1×4, 1×6, 1×8 sizes
- Cedar pickets from privacy fencing
- Cedar landscape ties
- Cedar 4×4 posts
Shop lumberyards for more specialty cuts if needed. For large beds, using cedar logs or half logs can make an attractive border. Just be sure any cedar products are certified for organic gardening use.
Cypress – A Worthy Contender to Cedar
If cedar proves tricky to source or too pricey, cypress is an excellent alternative. Grown across the southeastern United States, cypress shares many parallels with cedar:
- Native to southeastern US – Easier to find and affordable in this region
- Natural resistance to pests/rot – Durable against weathering
- Affordable and readily available – Provides great value
- Suitable for wet, humid climates – Tolerates moisture well
Cypress contains cypressene oil that deters pests and fungus. The heartwood is quite resistant to decay while the sapwood is more vulnerable. To identify quality cypress, inspect the wood closely.
Finding Quality Cypress Wood
Opt for cypress with mainly heartwood, which has a yellowish to reddish-brown tint. The sapwood is lighter colored and not as rot-resistant. rejected for having too much sapwood.
You can find cypress lumber at home centers or specialty hardwood dealers in dimensions like:
- 1×6, 1×8, 1×10 boards
- Landscape timbers
- Fencing planks
- Half round cypress logs
Cypress makes excellent raised beds that can last over 5 years. Just be sure to use 100% untreated cypress certified for garden use.
Other Durable Species Worth Considering
While cedar and cypress are top contenders, here are a few other rot-resistant woods that are suitable for raised beds:
- Redwood – Naturally resistant softwood good for outdoor use.
- Teak – Tropical hardwood renowned for weather/rot resistance.
- White Oak – Extremely durable outdoor wood but expensive.
- Locust – Hardwood with excellent decay/insect resistance.
Keep in mind these woods tend to be pricier or less available than cedar or cypress. But they remain good options for a sturdy and non-toxic raised bed frame.
Building the Frames and Boxes
Cedar and cypress are relatively soft, lightweight woods that are easy to work with using basic carpentry tools. No specialty tools needed! Both woods have a pleasing aroma when cut and can be stained or sealed for added protection.
When constructing the boxes, be sure to:
- Cut wood to the desired lengths and widths.
- Pre-drill holes to prevent splitting.
- Assemble using exterior screws, nails or bolts.
- Include corner posts for reinforcement.
- Level and square the beds.
Those DIY-averse can opt for prefabricated raised bed kits made of cedar or cypress. Just verify untreated all-natural materials were used.
Staining and Sealing Your Raised Beds
Though cedar and cypress resist decay naturally, adding a protective finish can help extend the lifespan of your raised beds. Look for stains and sealants safe for food gardens. Key steps include:
- Lightly sand each board using 120 grit sandpaper.
- Carefully wipe boards clean of any residue or dust.
- Apply 2-3 coats of water-based stain, sealer or wood protector.
- Allow 1-2 days of drying time between coats.
For optimal protection, stain and seal boards before assembling the raised beds. Reapply coating every 1-2 years as needed.
Plan Ahead to Get the Wood You Need
Raised garden beds are often built in late winter or early spring in preparation for the growing season. Visit lumber suppliers during the slower months when inventory is plentiful. Many mills and manufacturers:
- Process more wood in winter months
- Experience reduced building construction demand
- Have more time for specialty orders like cedar boards
- Offer promotions on off-season purchases
Allow several weeks for any custom cuts and 1-2 weeks for delivery. Planning ahead ensures you get the ideal wood on time.
Once your durable cedar or cypress raised beds are ready, it’s time to set them up for planting:
- Line the boxes with landscape fabric to prevent soil erosion.
- Fill with a quality potting soil mix for optimal drainage.
- Follow best practices for maintaining raised beds.
- Grow delicious fruits, vegetables and herbs in your chemical-free boxes!
The raised garden has a foundation with the right wood. Stick with rot-resistant cedar or cypress for raised beds that stand the test of time while keeping your plants safe and healthy.