With the rising popularity of raised bed gardening, some thrifty DIYers have pondered using inexpensive fiber cement siding as the structure for their raised beds. Materials like HardiePlank fiber cement panels are conveniently pre-sized for constructing framed enclosures for gardens. However, while creative repurposing often works beautifully, fiber cement has some drawbacks that make it less than ideal for direct ground contact and holding back heavy, moist soil.

Raised bed gardens are a wonderful addition to your home, and doing them right will increase the enjoyment (and savings) they provide. Let’s look at the arguments against using fiber cement siding for raised beds and what alternatives will give you a more lasting, healthy garden.


Why Fiber Cement Has Limitations for Raised Beds

While fiber cement siding contains cement, it has vulnerabilities when used in constant ground contact or to contain damp soil. Problems include:

Fiber cement contains wood pulp as reinforcing fiber filler. Like other wood products, the organic material will gradually break down and weaken with moisture exposure.

Fiber cement is designed as an exterior siding that doesn’t touch the ground. It’s not formulated for permanent burial where moisture is continually wicked into the material from the soil.

The thin panels of fiber cement bend under pressure. They require sturdy bracing to resist inward bowing from soil weight pressing outward.

Fiber cement is durable when installed on walls but easily snaps if you insert stakes or tools into the garden bed. 

Overall, the durability and performance of fiber cement degrades rapidly in constant wet soil contact. As fibers swell and pulp components deteriorate, the panels weaken and crumble. Expect fiber cement-raised beds to last one to three years at best.


Better Alternative Materials

cedar
Image Credit: Canva

Many other products are better suited for the demands of containing heavy, moist soil for vegetable gardens. Thick landscaping timbers are durable even in an untreated state. Cedar is a great choice that resists rot, fungus, and insects. 

Stone and masonry are among the best options. Bricks and blocks designed for exterior use will last decades with very little need for maintenance and repairs. The most long-lasting option is stone.

While stones aren’t as easy to place as brick and block, they’re virtually indestructible and completely weatherproof. 


Key Considerations for Designing Sturdy Raised Beds

To build a raised bed that successfully contains soil and supports plants, consider the following:

Gardens at least 12 inches deep allow ample root room for crops. Go 20 to 24 inches deep for potatoes or carrots.

Limit width to four feet maximum for accessibility from both sides without stepping into the bed. Wider than four feet, and you won’t reach the middle.

Infill garden beds with a mix of compost, coconut coir, peat, and amendments to improve drainage and nutrients. Don’t just use clay soil.

Use corner braces, rebar stakes, galvanized nails, or supports to strengthen the structure against soil pressure and prevent bowing over time.

Ensure the bed gets at least six hours of daily sunlight. Position near water sources and away from trees with invasive roots.

Proper planning and design is as important as the structural materials used when it comes to creating long-lasting raised beds that support thriving gardens.


So, Is Fiber Cement Worth Using for Raised Beds?

While fiber cement siding may seem like a convenient, affordable option for building raised bed enclosures, the composition and durability of fiber cement means it won’t perform well with constant direct ground contact. The wood components and fragility cause fiber cement raised beds to deteriorate rapidly and require frequent rebuilding.

For long-lasting, low-maintenance raised bed structures, choose materials designed to withstand outdoor exposure, such as landscape timbers or masonry. Or use cement board rather than weaker fiber cement if you want a panel siding material. Take time to construct reinforced frames and fill beds with enriched gardening soil. With smart planning, you can create durable raised beds that will sustain your gardens for five years or longer.


FAQs About Raised Garden Beds

What can be used instead of wood for raised beds?

Durable alternatives include bricks, concrete blocks, landscape stones, natural stones, and wood.


How long do raised bed gardens last?

Raised beds built from rot-resistant landscape timbers or thick exterior-grade woods last five to 10 years. Unprotected wood lasts three to five years. Brick or concrete block beds may last 10 to 20 years. Stone, depending on how it’s set, can last indefinitely.


How deep should raised garden beds be?

For adequate root space for most crops, make raised beds at least 12 inches deep. Go 18 to 24 inches deep for root vegetables like potatoes, onions, carrots, and parsnips. Deep beds up to 36 inches suit in-ground plants like tomatoes and cucumbers.


Can pressure-treated wood be used for raised beds?

Newer pressure-treated lumber approved for garden use is safer than in the past but may still leach compounds. Untreated cedar or redwood are better choices that avoid chemicals. Or use an interior liner with any wood.


How wide should a raised bed be?

Maintain raised bed width between two to four feet. Beds wider than four feet are difficult to reach across. Traditional row beds are three to four feet wide, with walking space between them. Smaller beds for lettuces and herbs can be narrower.


Editorial Contributors
avatar for Doug Sluga

Doug Sluga

Doug Sluga is a professional roofer and carpenter with ten years of experience in residential and commercial construction. His expertise spans the breadth of the roofing trade from minor repairs to laying shingles to framing trusses. These days he spends most of his time writing about roofing and the roofing industry.

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photo of Lee Ann Merrill

Lee Ann Merrill

Chicago-based Lee Ann Merrill has decades of experience writing and editing across a wide range of technical and scientific subjects. Her love of DIY, gardening, and making led her to the realm of creating and honing quality content for homeowners. When she's not working on her craft, you can find her exploring her city by bike and plotting international adventures.

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