Short Term use of PT Wood or OSB Plywood

Hey folks, I know the PT wood \ OSB wood has sort of questionable chemicals in it and I know there is a lot of debate about the leaching of said chemicals however, Is there any danger in using that type of wood as temporary frame work to dig out a hole?

I am building 4 new Hugelkultur beds as I have last year but quickly learned that a lot of rain or simply being clumsy can cause the sides to give out and either spill into the bed or ruin the edge that I leveled out. Due to the way I do the Hugels, digging ~24"-30" down into the soil and then framing the top and putting a 12" raised bed frame on it, I’d like to be able to support the side walls with 2’ wide pieces of OSB with some sort of center support until I am ready to throw the logs and other stuff in.

Last season when I built the 1st two veggie beds I kept messing up the level soil as well as the untouched, solid ground that the bottom 2x4 frame sits on causing it to become unstable \ unlevel which makes me crazy.

Because my yard has a noticeable slop, I make every effort to level the dirt for the frame to prevent sinking\twisting\other bad stuff. The dirt will be in contact with the soil for at least 4-6 weeks as I dig and gather the various wood pieces after work.

Using plastic to line it is not an option, (I’m lazy) I’ll go without the support as before if this idea for using my left over PT \ OSB wood is not safe for edible garden soil contact even for a short period.

As a point of note, the wood has no other real value as it is left over from a deck project and garage shelving so it getting wet or dirty etc is not an issue.

If anyone has any feedback it would be appreciated.


PT wood is just wood with copper. Totally safe.

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Agreed, the newer PT wood no longer has arsenic in it, so should be fine. Most of the health issues with OSB are that it off gasses some pretty nasty stuff for ~1 year, but since this is outside it should mostly blow away. And since you are using old wood and only for a short time in the soil, I would think it is OK.

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Thanks. Based on what you said about age, it is worth mentioning that the OSB plywood is about 2 or so years old at least.