Will my planter box kill me?

April 29, 2009 9:25 PM

Is heat-treated kiln-dried lumber safe for a raised planter box that may house vegetables?

I built a big planter box early this year out of some scrap (HT/KD) 2x8's. Initially, this was going to be home to some flowers to attract hummingbirds. My plan changed, the flowers are going on the deck, and now the big planter box is empty.

I know that pressure-treated lumber is filled with icky chemicals and is not for use around growing vegetables, but I'm not sure if heat-treated, kiln-dried lumber (HT/KD) is just as evil.

Can someone share their expertise in this?
Thanks!

posted by thinds66 to home & garden (5 comments total)

Perfectly safe. Dry lumber (either air-dried or kiln-dried) just has the moisture removed from green wood.
But remember that it is best to use a cedar or redwood for this type of thing since they are more resistant to rot. I found this out the hard way, I have raised beds that I've had to rebuild.
posted by artdrectr at 9:44 PM on April 29

"Heat-treated" means the wood was held at a high temperature for a certain amount of time to kill any insects hiding inside. This is done to prevent the spread of pest species. It's mostly an import/export international trade issue. I don't think heat treatment involves any chemicals.
posted by ryanrs at 10:07 PM on April 29

Agreeing with artdrectr and adding Teak and Cypress as candidate woods. Treat the boards with Tung Oil, which is food safe, will significantly extend the life of the wood and slow (but not prevent) the natural color change of the finish.
posted by EnsignLunchmeat at 10:12 PM on April 29

Yup. No problems. You are right about pressure treated. It will shrink your gonads.
posted by sully75 at 4:21 AM on April 30

The old arsenic containing pressure treated wood (CCA) was banned a few years ago. The new stuff (ACQ) uses a copper compound and is much safer (and less rot resistant). Even so, the EPA tested the old stuff and found that leaching only really occurred in really acidic soils, so it shouldn't be an issue. If you're still concerned about leaching, you can paint the inside with a couple coats of latex, or staple a layer of polyethylene over the wood.

Cedar, redwood, etc are also good candidates, but they're also very very expensive.
posted by electroboy at 7:10 AM on April 30