Cedar and redwood last longest, but pressure-treated lumber costs less

Cedar and redwood are the standard choices for raised beds because they resist rot naturally — cedar lasts 10 to 15 years, redwood slightly longer. Both are soft enough to work with hand tools and won't leach chemicals into soil. Redwood is harder to find outside the West Coast and costs more. Cedar is widely available and moderately priced, making it the most common choice for home gardeners.

Pressure-treated lumber (typically pine or fir treated with copper compounds) costs 30 to 50 percent less than cedar and lasts 15 to 20 years. Modern pressure-treated wood is safe for vegetable gardens — the arsenic-based treatments used before 2004 are no longer sold. The trade-off is that pressure-treated wood is heavier, harder to cut, and visibly industrial. Many gardeners accept this for the price and lifespan.

Untreated pine and fir rot within 3 to 5 years in wet soil and are not worth the money you save. Composite boards (wood fiber mixed with plastic) last 20+ years but cost two to three times more than cedar and are overkill for most home gardens.

Key Takeaways

  • Cedar is the best balance of durability, workability, and cost for most home gardeners, lasting 10 to 15 years without chemicals.
  • Pressure-treated lumber lasts longer and costs less but is heavier, harder to cut, and looks industrial in a garden setting.
  • Untreated pine and fir are false economy — they rot in 3 to 5 years and will cost you more in replacement labor than you save upfront.
  • Redwood is excellent but scarce outside the West Coast and costs more than cedar for similar performance.
  • Composite boards last the longest but cost significantly more and are unnecessary for most home raised beds.

How to choose based on your budget and timeline

If you plan to keep the bed for 10 years or longer and want to avoid replacing it, cedar is the practical choice. A 4-by-8-foot cedar bed costs roughly $150 to $250 in materials, depending on board thickness and your region. You build it once and do not think about it again.

If you are budget-conscious or building multiple beds, pressure-treated lumber cuts the material cost to $80 to $150 per bed. You will replace it once in 15 to 20 years, but the lower upfront cost often makes sense for gardeners testing the hobby or working with limited space. The weight makes it harder to move or adjust later, so plan the location carefully.

Redwood works if you live on the West Coast and have the budget — it is beautiful and durable but rarely worth shipping across the country. Composite boards make sense only if you want a bed that will outlast your house and do not mind the plastic appearance or the cost.

Board thickness and dimensions matter for stability

Use boards at least 2 inches thick (actual thickness, not the nominal "2x" label). A 2-by-10 or 2-by-12 board is standard for raised beds because the extra height keeps soil off the ground and gives roots room. Thinner boards (1-inch nominal, or 3/4-inch actual) flex under the weight of wet soil and will bow outward within a season or two.

For beds taller than 12 inches, reinforce the corners with metal brackets or wooden corner posts. Soil is heavy — a 4-by-8-foot bed 12 inches deep holds roughly 2,500 pounds of wet soil. Without bracing, the boards will spread and the corners will fail.

Cedar and redwood are softer and flex slightly more than pressure-treated wood, so do not skimp on thickness if you choose them. A 2-by-12 cedar bed will hold its shape longer than a 2-by-10.

Avoid wood that will poison your soil

Do not use railroad ties, old utility poles, or reclaimed wood from construction sites. Railroad ties are soaked in creosote (a coal tar product) that leaches into soil for decades. Utility poles are treated with pentachlorophenol, which is toxic to plants and people. Reclaimed wood may have been treated with unknown chemicals or painted with lead-based paint.

Treated plywood and oriented strand board (OSB) are not suitable — the glues and resins break down in wet soil and contaminate the bed. Stick to solid boards.

Modern pressure-treated lumber sold at home centers is safe. It is treated with copper-based compounds (ACQ or CA) that do not leach significantly into soil at levels that harm vegetables. If you are concerned, line the inside of the bed with landscape fabric to create a barrier between the wood and soil.

Where to buy and what to expect

Cedar and pressure-treated lumber are stocked at every major home center — Home Depot, Lowe's, and local lumber yards. Cedar is usually in the outdoor section; pressure-treated is in the framing lumber aisle. Prices vary by region and season; spring is peak demand and prices are highest.

Redwood is harder to find. If you live on the West Coast, local lumber yards carry it. Elsewhere, you may need to special-order it or buy online, which adds shipping cost. Composite boards are sold at home centers but are usually special-order items.

Ask the lumber yard to cut boards to length if you do not have a saw. Most will do this for free or a small fee. Cedar and redwood cut cleanly; pressure-treated wood is dusty and harder on saw blades, so some yards charge a bit more.

Assembly and maintenance extend the life of any wood

Assemble the bed on level ground — uneven ground creates gaps where water pools and accelerates rot. Use galvanized or stainless steel screws (not nails), which resist rust and hold better as the wood moves with moisture. Galvanized nails will rust and stain the wood.

Cedar and redwood do not need sealing or staining to resist rot — that is why you chose them. Sealing them actually traps moisture and speeds decay. Pressure-treated wood also does not need sealing. If you want to change the color for appearance, use a water-based stain, not an oil-based one.

Every few years, check the corners and the bottom boards for soft spots. If the wood feels spongy when you press it, that section is rotting and needs replacement. Catching it early means replacing one board, not the whole bed. Cedar and redwood rot from the outside in, so the damage is visible. Pressure-treated wood rots more slowly and the damage may be hidden until the board fails.

Frequently Asked Questions

Can I use untreated pine to save money?

No. Untreated pine rots in 3 to 5 years in wet soil, and you will spend more replacing it than you save on the initial purchase. Cedar costs more upfront but lasts 10 to 15 years and is worth the difference.

Is pressure-treated wood safe for growing vegetables?

Yes. Modern pressure-treated lumber uses copper-based compounds that do not leach into soil at harmful levels. The arsenic-based treatments used before 2004 are no longer sold. If you want extra assurance, line the inside of the bed with landscape fabric.

How deep should a raised bed be?

Ten to 12 inches is standard for most vegetables. Root vegetables like carrots and potatoes need 12 inches or more. Shallow-rooted plants like lettuce and herbs can grow in 6 to 8 inches. Deeper beds hold more moisture and give roots more room, but they also cost more and are heavier to fill.

Do I need to treat the wood with anything after I build it?

No. Cedar, redwood, and pressure-treated wood all resist rot without sealing. Sealing actually traps moisture and speeds decay. If you want to change the appearance, use a water-based stain, but it is not necessary for durability.

What size should I make my raised bed?

Four feet wide by eight feet long is standard — it fits in most yards and is straightforward to reach across from both sides without stepping in the bed. Narrower beds (2 to 3 feet wide) are easier to maintain but use more wood per square foot of growing space. Avoid beds wider than 4 feet unless you do not mind stepping in to reach the center.