Is today’s brown pressure treated lumber safe for gardening? We still get this question all the time. The short answer is yes, with a few caveats.

According to Scott Leavengood, Director at Oregon Wood Innovation Center, “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. However, I haven't seen any research that suggests the level of the chemicals is significant enough to be of concern for human health.”

Back in the 1990’s, many of you were made aware of the dangers posed by the old-school CCA (chromium, copper & arsenic) treatment. CCA-treated wood has been restricted since 2004 to foundation construction only. 

Today most pressure-treated wood uses copper-based compounds, including copper azole (type C), or CA-C, which is what we stock here at Freres Building Supply. Copper is considered much less toxic than arsenic. However, the green pressure treated lumber is still CCA-treated which contains arsenic and should not be used for raised garden beds.

If you are still concerned about the copper, consider lining the inside of your raised beds with plastic before you fill it in with dirt.

Here at Freres Building Supply we stock other materials for raised garden beds as well. Rough cut 2x10 cedar, concrete blocks & more. Come see us and we will help you get that project started!

Sources:

http://www.allweatherwood.com/treated-wood-safety/

http://exteriorwood.com/apcl.htm

http://extension.oregonstate.edu/question-of-the-week/raised-bed-lumber-pressure-treated-safe

http://www.gardensalive.com/product/the-new-treated-woods-safe-for-garden-use/you_bet_your_garden

http://homeguides.sfgate.com/can-use-pressuretreated-lumber-raised-beds-80963.html