The Safety of Materials Used for Building Raised Beds (2024)

FAQs

What materials are safe for raised beds? ›

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.

Bagged raised bed potting mix is commonly used in small raised beds, but you can purchase it in bulk from local landscape companies. Another option is to make your own potting mix by blending equal parts of topsoil, compost, and sand to create a quality mix that's appropriate for most vegetables, herbs, and flowers.

The galvanization process involves coating the steel with zinc, which serves as a protective barrier against corrosion or rusting. This means that there won't be any harmful chemicals leaching into your soil or vegetables, making it a safe and reliable option for your food garden.

Raised beds offer gardeners many benefits over in-ground gardening. They come in all shapes, sizes, and materials — including wood, wood composites, and metal. If you've never tried growing in raised beds, you might be surprised at how much better plants grow — and how much easier they are to maintain.

Wood treated with Chromated Copper Arsenate (CCA) is NOT considered safe. CCA is a well-documented health hazard, making it unacceptable for a raised garden or for contact with anything edible.

Stone Is the Most Durable Raised Bed Material

Stone is also food-safe and can often be locally sourced.

A: You should avoid putting rocks in the bottom of your garden bed. A common myth is that this will improve drainage. Instead, this can actually increase water saturation levels as well as allow gravel to mix in with your soil, which can prove very difficult to remove later on.

Many experienced gardeners recommend lining raised beds for these reasons: It provides insulation for the soil and helps control temperature fluctuations. It helps with soil retention. It separates weeds from seeds.

Should I line my raised garden bed with plastic? ›

Material 5: Plastic or Tarp

This could cause water to pool and build up, causing problems like rot in the roots. It may be better to use plastic as a liner on the inner sides of a raised garden bed, but use a more permeable material for the bottom, such as landscape fabric or wire mesh.

Raised garden beds can be constructed from a variety of safe and sustainable materials. Cedar or redwood are two great options for wood as they are naturally rot-resistant and won't leach harmful chemicals into the soil.

Raised beds made of cinder blocks or concrete blocks

Cinder blocks and concrete blocks are very inexpensive (typically $2 to $3 a piece at home improvement centers), and they make it really easy to build the outline of a raised garden bed.

On average, a DIY raised bed constructed from wood will cost $25 to $50 per square foot. To have a wooden raised bed constructed and installed for you, budget for at least $100 per square foot. (Find a kitchen garden company in your area.)

You don't have to build the frame out of wood for your raised bed garden to be truly organic. Other options are bricks, flagstone, or even large river rocks. (Add a non-toxic garden bed liner to hold the soil in place.) Steer clear of concrete; it may leach into your soil and alter soil acidity.

He stated in a bulletin titled, Treated Wood in Raised Bed Gardening, “Scientific evidence and data have shown that using pressure treated wood for raised bed or box gardening is safe to adults and children in terms of the plants grown and used in these containers.” He further explains, “All chemicals in consumer ...

We recommend buying high-quality, nutrient-rich soil in bulk. Or, you can make a soil mix with equal parts topsoil, organic materials (leaves, composted manure, ground bark), and coarse sand.

You can line your raised bed to make it more durable and to prevent toxics from leaching into the soil. For lining, use landscape fabric found at garden supply stores or cloth fabric from clothing. Avoid non-porous plastic, as it can retain too much water and discourage beneficial insects and worms.