Lining the boxes?

Some of the folks in our new garden group want to line the inside of the boxes to protect the wood, not the bottoms, only the inside walls of the boxes. Any suggestions? Some want black plastic, some are talking paint/primer, some want metal sheeting. Geesh! I think the wood will last for several years as is...it's Douglas Fir 2"x8" as 4'x8' frames. They are stacked two high for a depth of 15" because everyone thought the 8" depth was not deep enough. These are gardeners new to SQF and haven't tried it yet. Sooo, any suggestions for lining the frames to protect the wood from moisture from the soil?? Thanks!

Hello PNG_Grandma! I know someone that lined the inside with black plastic and they said it worked fine. Another person that used pond liner (expensive) that also worked.
I can give you my experience with Douglas Fir and hope this helps. My oldest raised bed, (9 years old now) is a 4'x8'x24". It was never painted and exposed to the weather (lots of rain in the Pacific Northwest) all this time and the wood is still not rotted at the bottom. I did paint it this year to match the other bed and hope that it will give me a few more years before it rots. (It will probably collapse since I said something! lol)
I have two 4'x4'x12" beds that I stained. (top edge, outside walls and the raw cut ends NOT the inside or bottom edge that touches the ground) One 4'x8'x24" that I painted (Kilz primer I had on hand), and again, NOT the inside or bottom edge that touches the ground.
I would not seal or paint anything that touches the soil itself due to possible chemicals leaching into the soil mix. I have learned that you can grow in 6 inches of Mel's Mix! It is a highly productive soil mix and if you follow the book it will work!
I am a new to the Square Foot Gardening method this year and hope that your group gets many years of gardening enjoyment!

There IS an option for sealing things with a painted-on sealer.

In the roof-coating and/or foundation-coating department, look for a WATERBASED asphalt emulsion -- the ingredients should read something like asphalt, kaolin (clay), and water.

THAT can be used for waterproofing your frames, pots, etc....once it's dried, it's nearly completely inert, as it's then just asphalt.

The company I used to work for doesn't make theirs any more, but there were customers who used it to line ponds in their gardens...with no problems for the koi.

Thanks HappyCamper and LaFee, we appreciate your comments and suggestions. Honestly, I'm totally against doing ANYTHING to the insides of our garden boxes but I was out-voted. As of right now the boxes have been sprayed with Kilz on the insides and will soon have a black plastic attached to the inside over the Kilz. I think this is over-kill, but hey, if that's what the majority wants, well...I'm just the organizer. The whole project is an experiment. Umpteen neighbors are adding their own suggestions and 2 cent's worth, most is pretty outrageous and we just nod and smile, then do what we already planned!

The 25 boxes we bought last spring were supposed to be cedar. We lined a couple of them and left a couple more alone, but then 2 of the boxes started warping and started popping their screws. Katie wants to line them all. I don't want to fool with it. Since the rain is keeping me from filling these boxes anyway, we'll probably have to wait until spring. So, what's the current wisdom on lining or painting/spraying/staining these boxes?

countrynaturals wrote:The 25 boxes we bought last spring were supposed to be cedar.

You bought 25 4-foot square garden boxes? Where? How?

I'm experimenting with painting now. But I'm not worried about stuff leaching out of paint. You get more toxins sitting in a car these days (that "new car smell" is mostly vinyl).

If it was me, I'd try to get them some place dry or at least covered with a tarp until you know what you want to do.