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

FAQs

The Safety of Materials Used for Building Raised Beds? ›

Avoid using older types of wood treatments such as CCA, creosote, and Penta-treated lumber. Research from Oregon State University showed that pressure-treated lumber does increase soil copper concentrations by a minor amount, but only within 1 inch of the raised-bed edge.

Let's wrap up with some recommendations about the use of treated lumber in landscape projects. Even if you could find them, it is best to avoid CCA-, creosote- and Penta-treated lumber.

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 ...

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.

Studies have shown that arsenic from wood treated with CCA leaches into the soil and that copper, although much less toxic, leaches from ACQ and copper boron azole (CBA, a variant of CA-B).

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.

At this time the manufacturers started using micronized copper azole (CBA) and various other copper compounds to treat lumber. Even though these copper species are considered less toxic than CCA, they may still pose health risks.

Yes, the "new" pressure treated wood is safe for use for raised garden frames... with a few precautions! Up until 2003, the most common preservative used for pressure treated wood was chromated copper arsenate (CCA), a compound using arsenic as its primary rot protectant.

Drawbacks of Gardening with Plywood Boxes

As plywood is not a naturally porous material, it can be hard to keep the soil moist and the plants healthy. Additionally, plywood can be prone to warping and cracking over time, which can be a problem if you are not able to inspect and repair your boxes regularly.

Uses for Pressure-Treated Wood

Ground contact lumber can be used for raised garden beds for ornamental plants. If edibles are to be planted, you can line the pressure-treated boards with plastic. This will keep soil from making contact with the wood.

Does corrugated metal leach into soil? ›

Well, the answer is yes. They are safe for gardening. The zinc coating used on metal raised modular raised garden beds needs to break down the acidity before it can start seeping into the soil. Most garden soils have a neutral pH, so zinc will have little effect on your garden.

Zinc, in its finished form, does not provide a toxicity risk. However, like most things, if too much zinc gets in your system, or the metal has significantly deteriorated, the underlying steel can potentially leach toxins.

As a final reminder, avoid lining your garden beds with plastic. Doing so prevents drainage and could drown your plants' roots with too much water. If you have a weed and pest problem, consider installing a combination of metal mesh and fabric or hardware cloth and cardboard to address both issues simultaneously.

The safety of pressure treated lumber for raised bed gardens has been examined by several researchers. From what I've seen, the consensus is that the chemicals do leach out of the wood into the soil and are uptaken by the plants in very small amounts.

CCA residues on your skin do not get in your body. However, they may cause redness and swelling. Ingesting low levels over the long-term can lead to hair loss and skin changes including thickening or darkening of the skin. It can also increase the risk of skin, bladder, liver, and lung cancer over a lifetime.

By January 2004, the EPA will no longer allow pressure-treated wood containing CCA to be used for residential applications such as children's play structures, decks, picnic tables, landscaping timbers, residential fencing or walkways.

Pressure-treated lumber is not recommended for raised beds for growing vegetables. Never use railway ties treated with creosote. This wood is dark in colour and smells like petroleum. The chemicals used to treat this wood are extremely toxic.

Shop Now for Your Own Aluminum Raised Garden Bed!

With their lightweight, rust-resistant nature, aluminum raised garden beds provide the perfect solution for easily growing healthy plants. Don't wait any longer to transform your outdoor space into a flourishing oasis.

Cinder blocks haven't been mass produced with fly ash in the U.S. for 50 years, though. The cinder blocks that you buy in the store today are actually concrete blocks and totally safe. Unless you're using antique cinder blocks, there should be no reason to worry, especially when cinder block gardening for vegetables.

#3 is Polyvinyl (PVC). This plastic contains phthalates, which are known health hazards unsafe for food or garden soil. #4 is Low-Density Polyethylene (LDPE). Food-storage safe and not known for leaching chemicals into food or soil, LDPE is a very safe material for a raised garden.