Kim -- I used cedar fence slats (two high for 11-12 inches). They are treated, but with the new non-toxic compound. I even used the slats for the anchoring stakes. (Cut down the middle and into 3 sections = 6 stakes; drive 8-12 inches into the ground.) (And yes, they are strong enough for raised beds with a soilless mix.)

At 93c each, bargain! Ended up spending about $100 (including screws) for almost 400 square feet of beds.

I have used Trex and Cedar. I found Trex heavy, expensive. Other than that, nothing wrong with it that I could see. However, I've grown to love my Cedar. It will last (almost) forever, resists rot, repels insects, is easy to work with. I bought cedar with honest dimensions, i.e. a full 1" wide by a full 7" deep. If you are going to use pine, I would use wood that is at least 2" wide. I don't think it's a good idea to add any contaminants to a vegetable garden, so for me painting is not only unnecessary, but expensive in time and money. Just plain raw wood is just fine. If you want pretty for out front, invest in Belgian Blocks at $2.50 each. But if you end up being like the rest of us, you will want to add squares as fast as you can, and that means doing them inexpensively whenever you can.

Yes you certainly can do that. The real nasty stuff that used to be used to treat wood up until the mid-90's is no longer used and its highly regulated. Its definitely going to make them last longer. Mine have been in place for 12 years now and still going strong. My biggest mistake was that I didnt fasten them together correctly. But, if your dead set against using treated wood, use the other stuff. You will just be replacing it a lot more often making it more expensive.

I used treated 2x10x8s and cut one in two to make the ends.
Even though today's treated wood is supposed to be safe you can line the inside of the bed with plastic as a precaution.
And I did.

I almost fainted dead away when I saw the price of cedar, so I went with 2" white wood. It will be several years before I have to replace it, (at least 7) and it will still be cheaper than cedar. I figure I might want to move a few things around in 8 years anyway. Not a problem for me.

j

janzee...I dont think that will last for 7 years but I guess you can just go out and replace it all again after that. If you live in a place that has hard winters it wont. As mentioned earlier mike, there are other options that are safe, cheap, and it doesnt take a long time to do. I think Jay had a good idea too. It's worth it to save as much money as you can in this kind of economy so I would paint the outside and top of the wood to make it last longer

I'm going into my 4th year with just 2x6 pine and they still look fine.
Keski

I am using 2" x 10" x 8' untreated pine. Then I am treating the boards with raw linseed oil. Don't know how long they will last. But where I live, cedar was at least 3 times more expensive than the pine.

I am wondering wheter I should add any supports to the 8' beds in the middle to keep them from bowing out. Or is the 2" thickness adequate to prevent bowing.