Treated Lumber in the Garden - Indiana Yard and Garden - Purdue Consumer Horticulture

Treated Lumber in the Garden

Gardening in raised beds can be just the answer for would-be gardeners who would love to grow their own vegetables and flowers but lack the space or physical ability for a traditional garden. However, recent controversy regarding chemical wood preservation treatments has left many gardeners wondering about the safety of treated lumber.

The Environmental Protection Agency (EPA) recently announced that lumber treated with chromated copper arsenate (CCA) will be phased out for use in consumer/residential products over the next couple of years.

The EPA is not requiring or recommending replacing existing CCA-treated structures at this time. Although the EPA does say that any reduction in exposure to arsenic is desirable, it has not concluded that there is an unreasonable risk associated with CCA-treated products. However, people who are concerned about existing structures in their yards or gardens can seal the treated wood every 2 years with an oil-based stain or insert a plastic liner to eliminate contact with soil.

So what will gardeners have to choose from for landscape projects? No doubt new products that are more environmentally friendly will be developed in the next few years. Alkaline copper quaternary (ACQ) is a relatively new wood treatment that is already being marketed in some areas. This product is higher in copper than CCA but is free of arsenic.

There are alternatives to treated lumber, including synthetic wood, such as that made from recycled plastic, vinyl fencing and naturally rot-resistant woods like cedar and redwood. Materials besides wood also can be used, such as stone, concrete block and brick.

For more information regarding the phasing out of CCA, visit the EPA Web site or


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Disclaimer: Reference to products is not intended to be an endorsement to the exclusion of others which may have similar uses. Any person using products listed in these articles assumes full responsibility for their use in accordance with current directions of the manufacturer.
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