How to protect my wooden raised beds

[Paulzie]

Hello all, I'm new to this forum...and I have searched and searched for an answer to this but I havent found an answer I'm totally comfortable with.

So my wife and I are building raised beds over these strange squares of gravel in our backyard...

She bought pine for the beds because it is cheaper than redwood/cedar ...however it is not naturally rot resistant and cant stand up to the weather like its red counterparts...this I'm sure you all know.

We want a completely organic edible garden...and I'm afraid anything I put on the bed frames will leech into the soil.

But I don't want to have to rebuild them every year either.

I have seen that some people paint the wood or use shellac... but I don't know of any NO VOC paints...and shellac is not great for outdoor use. Others have mentioned linseed oil...but I read that linseed oil contains drying agents that are toxic (including arsenic)

I was thinking of using marine spar varnish since it is a super protector from UV and water damage...however I havent found out if anybody has used it and whether or not it can leech harmful chemicals into the soil.

Any advice would be greatly appreciated... I would like to spend as little as possible, so if we can use our pine and throw a couple of coats of varnish...that would be the best.

This is also to be used next year, so as far as drying is concerned...I am sure most of the gases will have dissipated in two seasons.

Thanks!

[brewerjamie15]

I use raised beds as well. I also use pine boards like you. I use 2x10's and have 4x4's as anchoring systems in the corners. I thought about lining the inside of the boards with plastic, painting them, etc. There are no VOC paints available, but I decided that I was not going to use anything at all. I didn't paint, line with anything, just plain jane. That was 3 years ago. I recently did some digging in the beds to get ready for a redesign of the bed layout. My boards show virtually no sign of decomposition. I'm pretty happy about it and although I plan to eventually switch to 6x6's, the 2x lumber is a great way to go.

[Charlie MV]

I'm a retired cabinet maker and brewerjamie is right. There aren't any finishes I'd trust my food to that will do any good toward preserving raw wood. Thicker lumber is your best bet. You'll get 3 or 4 years out of 2 by material and longer out of thicjer stuff. I'm curious if anybody is up on that lumber made from recyclables and whether it out-gases anyhing toxic if it were used. I know it makes wonderful long lasting decks.

[cynthia_h]

Charlie, your comment just motivated me to look up Trex (the only one of the plasticized/resin lumber-like compounds whose name I know).

There is a link to the .pdf of the MSDS (chemical safety sheet) for Trex at:

https://www.trex.com/technicalinfo/msds.aspx

According to the MSDS, there are no hazardous fumes released from Trex, and off-cuts may be disposed of with regular refuse. There are no special disposal requirements for Trex.

So it sounds safe for planter boxes, if you have some lying around. I have no idea of its price, but FreeCycled wood (free!) is definitely cheaper, and knotty pine (and I do mean with knots) is most likely cheaper.

My basic veggie "planter box" this year is made of cinder blocks simply laid end to end in a rectangle, without any mortar or anything holding them in place. They've stayed put since April. We'll see, this winter, when the rains come, whether they stay in place for good. But they're definitely chemically inert, since they are re-re-re-used (DH has used some of them since college for the good old cinder blocks & boards bookshelves)!!!

Aanndd nnootthhiinngg bad has happened from us eating our home-grown produce. Yyeett.

Cynthia H.
USDA Zone 9, Sunset Zone 17

[Paulzie]

Thanks for the great advice guys...I think I will just use the naked pine and hope for a long life!