Cedar and redwood are the most durable choices for a raised bed, lasting 10 to 20 years without treatment, while pressure-treated lumber costs less but requires careful selection to avoid harmful chemicals.
The wood you choose determines how long your bed will last before rot sets in, how much you'll spend upfront, and what touches your soil and food. Cedar and redwood naturally resist decay because they contain oils that repel insects and fungi. Pressure-treated lumber (wood infused with preservatives) costs 30 to 50 percent less than cedar but has changed over the years—modern pressure-treated wood sold in the United States no longer contains arsenic, though older beds may. Untreated pine and spruce are cheap and straightforward to find but rot within 3 to 5 years in wet soil.
Your choice also depends on bed depth, climate, and whether you're willing to replace the wood eventually. A shallow bed in a dry climate can use pine; a deep bed in a wet region should use cedar or redwood. If budget is tight, pressure-treated lumber is safe for vegetables when you follow one rule: use only lumber marked for ground contact (not just "above ground"), and keep the wood from touching the soil directly by lining the bottom with landscape fabric or hardware cloth.
Key Takeaways
- Cedar and redwood last 10 to 20 years without treatment and are safe for vegetable beds, but cost two to three times more than pressure-treated lumber.
- Modern pressure-treated lumber sold in the United States is safe for food gardens when you choose boards marked for ground contact, not above-ground use.
- Untreated pine and spruce are affordable but will rot within 3 to 5 years when in contact with wet soil.
- Line the bottom of any raised bed with landscape fabric or hardware cloth to keep wood from rotting faster and to block burrowing pests.
- Board thickness matters: use at least 2-inch lumber (actual thickness 1.5 inches) so the bed doesn't warp or collapse under the weight of soil and water.
Cedar and Redwood: The Long-Term Investment
Cedar and redwood are softwoods, but their natural oils make them decay-resistant in ways that pine cannot match. Western red cedar is the most common choice for raised beds and will last 15 to 20 years if you keep it out of standing water. Redwood is similar in durability and appearance but is less widely available outside the western United States. Both woods are naturally rot-resistant without any chemical treatment, so they're the safest choice if you want to avoid any question about what's touching your soil.
The trade-off is cost. A 4-by-8-foot cedar bed kit or boards will run $150 to $300 or more, depending on your region and whether you buy pre-cut kits or individual boards. If you're building multiple beds or a very large one, that adds up fast. Cedar also requires some maintenance: it will gray over time if left untreated, though that's cosmetic and doesn't affect function. You can stain or seal it to keep the color, but that's optional.
Redwood is harder to source in many parts of the country and may cost even more than cedar. If you live in the Pacific Northwest or California, redwood is easier to find. Elsewhere, you may need to special-order it or accept that cedar is your best natural-wood option.
Pressure-Treated Lumber: Safety and Cost
Pressure-treated lumber is wood infused with chemical preservatives under pressure, which forces the chemicals deep into the wood fibers. In the United States, the standard preservative since 2004 is copper-based (usually copper azole or alkaline copper quaternary), not arsenic. If your raised bed is older than 2004 or you're buying reclaimed lumber, have it tested or assume it contains arsenic—don't use it for vegetables. New pressure-treated lumber is safe for vegetable gardens.
The catch is that not all pressure-treated lumber is the same. You must buy boards labeled for ground contact, not "above ground" or "deck" use. Ground-contact lumber has a higher concentration of preservative and is rated to touch soil. Above-ground lumber will rot faster when in contact with wet soil. Check the stamp on the end of each board—it will say "ground contact" or "above ground." Ground-contact boards cost slightly more but are worth it for a raised bed.
Pressure-treated lumber lasts 15 to 20 years, similar to cedar, and costs $50 to $100 for a 4-by-8-foot bed. The preservatives can leach into soil over time, but studies show the amount is too small to harm vegetables. Still, if you're uncomfortable with any chemical in your bed, cedar or redwood is the better choice for your peace of mind.
Untreated Pine and Spruce: When Budget Is the Priority
Untreated pine and spruce are the cheapest options—often $30 to $60 for a 4-by-8-foot bed—and they're straightforward to find at any lumber yard. They're also straightforward to work with: soft wood is lighter and easier to cut and nail than cedar. The downside is durability. Without treatment, pine and spruce will begin to rot within 3 to 5 years when in contact with wet soil. In a very dry climate or if you're willing to replace the bed every few years, this is a reasonable trade-off.
If you choose untreated wood, line the bottom with landscape fabric or hardware cloth to slow rot. This keeps the wood from sitting directly in wet soil and extends its life by a few years. You can also paint or stain untreated wood with a non-toxic sealant designed for vegetable gardens, though this requires upkeep and doesn't may provide longevity.
Untreated wood is also a good choice if you're building a temporary bed—for example, if you're renting and plan to take the bed with you, or if you want to experiment with raised beds before investing in cedar.
Board Thickness and Dimensions Matter
Regardless of wood type, use boards that are at least 2 inches thick (actual thickness 1.5 inches after milling). Thinner boards will warp, bow, and eventually collapse under the weight of soil and water. A 4-by-8-foot bed holds roughly 32 cubic feet of soil, which weighs 800 to 1,200 pounds depending on moisture. Thin boards cannot handle that load.
For a bed deeper than 12 inches, consider using 3-inch boards or adding internal bracing. A 2-by-12 board (actual dimensions 1.5 by 11.25 inches) is the standard for most home gardens and provides enough depth for most vegetables. If you're building a very large bed (longer than 8 feet), add a center support board running lengthwise to prevent the long sides from bowing outward.
Board width also affects cost and appearance. A 2-by-12 costs more than a 2-by-8, but the extra depth is useful for root crops like carrots and potatoes. A 2-by-8 is fine for shallow-rooted crops like lettuce and herbs.
Lining the Bottom to Extend Wood Life
Whatever wood you choose, line the bottom with landscape fabric or hardware cloth before filling with soil. This barrier slows the decay process by keeping wood from sitting in constant contact with wet soil and prevents burrowing pests like voles and gophers from entering the bed from below.
Use landscape fabric rated for 10+ years of outdoor use (usually labeled as "weed barrier" or "landscape fabric"). Lay it flat on the ground inside the bed, overlapping seams by at least 6 inches. You can also use hardware cloth (a metal mesh) if you're concerned about burrowing pests—it's more durable than fabric but costs more and is harder to work with. Many gardeners use both: hardware cloth on the bottom for pest protection, then landscape fabric on top to prevent soil from falling through the mesh.
This lining doesn't make untreated wood last forever, but it can add 2 to 3 years to its life by reducing direct soil contact.
Comparing Wood Types at a Glance
| Wood Type | Expected Lifespan | Cost for 4×8 Bed | Best For | Main Drawback |
|---|---|---|---|---|
| Cedar | 15–20 years | $150–$300 | Long-term beds, peace of mind | High upfront cost |
| Redwood | 15–20 years | $150–$350 | Long-term beds (West Coast) | Hard to find, expensive |
| Pressure-treated (ground contact) | 15–20 years | $50–$100 | Budget-conscious gardeners | Contains preservatives |
| Untreated pine/spruce | 3–5 years | $30–$60 | Temporary beds, tight budgets | Rots quickly |
Frequently Asked Questions
Can I use reclaimed or old wood for a raised bed?
Reclaimed wood can work if you know its history. Avoid old pressure-treated lumber (pre-2004) because it likely contains arsenic. Reclaimed cedar or redwood is fine. If you don't know what the wood is or what it was treated with, don't use it for vegetables—the risk isn't worth it.
Is pressure-treated wood safe for growing food?
Yes, modern pressure-treated lumber (post-2004) is safe for vegetable gardens. The preservatives used now are copper-based, not arsenic. Buy boards marked for ground contact, and line the bottom with fabric to reduce any leaching. If you're still uncomfortable, cedar is the alternative.
How do I prevent my wooden bed from rotting faster?
Line the bottom with landscape fabric or hardware cloth to keep wood out of direct soil contact. Avoid letting water pool inside the bed—may support good drainage. You can also explore a non-toxic wood sealant designed for vegetable gardens, though this requires reapplication every 1 to 2 years.
What's the difference between 2-by-8 and 2-by-12 boards?
A 2-by-8 board is 7.25 inches deep (actual measurement), and a 2-by-12 is 11.25 inches deep. Deeper beds are better for root crops like carrots and potatoes. Shallow-rooted crops like lettuce and herbs do fine in a 2-by-8. The 2-by-12 costs more but gives you more growing options.
Can I use treated wood from a deck or fence?
No. Deck and fence lumber is marked for above-ground use, not ground contact, and will rot faster when touching soil. You need boards specifically stamped for ground contact. Check the end of each board before buying.