Raised bed lumber, pressure treated safe? (2024)

FAQs

Is pressure treated wood safe for raised beds? ›

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 ...

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.

The chemicals used to pressure treat wood aren't safe for humans, this is why non-pressure treated wood is still required for use indoors, and why builders recommended that you only use pressure treated lumber for your outdoor projects like decks, pergolas, etc.

The treated wood can leach toxic chemicals for many years, so it would be wise to assume that the wood remains toxic. That said, there are a number of strategies you can use to minimize exposure of your raised veggie garden to the treated wood, as noted below.

Do plants absorb the preservative in pressure treated wood raised garden frames? Yes, plants can absorb these preservatives, but tests have shown that the amount of preservative leached from the newer PT wood products is so low that it is virtually undetectable.

A: 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.

Using an eco-friendly wood treatment is a great way to increase your confidence that your raised beds will last a long time. I recommend at the very least coating your lumber in linseed oil or beeswax to preserve them for the long haul.

Untreated wood: Cedar and redwood are popular choices because they naturally resist rot and insects, and they do not need chemical treatments that could potentially harm your plants.

The amount of leached chemicals generally drops quickly within a short distance from where soil is in contact with the treated wood. If you follow safety precautions around treated wood, you should not have any health effects as a result. However, you should avoid exposure to the smoke or ash from burning treated wood.

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.

Is pressure-treated wood safe for food? ›

Even though the new pressure-treated woods are considered safe, Wolmanized Outdoor, according to its Web site, does not recommend using pressure-treated wood where the preservatives may become a component of food.

In summary, if you're using newer, safer treated wood for non-edible plants with proper precautions like barriers, then yes, it can be a relatively safe option.

The disposal of treated lumber by burning has serious health and environmental risks. In fact, it's illegal to burn in all 50 states. Treated wood is also called CCA lumber. CCA is an abbreviation of Copper, Chromium and Arsenic.

Although arsenic is a carcinogen, manufacturers insist that the old, treated wood is safe for people, plants and animals when used as recommended. However, advocacy groups maintain that the chemical can rub off on contact and that the lumber remains dangerous for 10 to 15 years.

The arsenic in CCA-treated wood can leach to the surface and get on the skin if you touch it. You could accidentally swallow residues if you eat, smoke, or put your hands in your mouth after touching the treated wood.

The Best Types of Wood for Raised Beds

It's best to use untreated wood to build your raised garden beds, preferably a type of wood that won't decay quickly, such as cedar, redwood, or hemlock. Both the type of wood that you might find for sale and its affordability will vary based on where you live.

The Type of Wood Used

Cedar, redwood, cypress, and hemlock are all types of wood that don't decay or rot quickly, and they can be expected to last anywhere from 10 to 20 years. Check which of these durable boards you can find locally sourced. My preference is always untreated cedar.