Yes you can. The only problem with it you have already noted - much of it doesn't last long although there are exceptions.

FYI the former provision on using treated lumber around food crops doesn't extend to those using the newer treatment processes. The arsenic pressure treating was restricted/discontinued for most of public sales in 2002. Most common brands of pressure treated woods make their treatment process public on their websites and some will indicate "safe for use around food crops".

Dave

I would think it would work. My DH made me a planter box out of untreated pine 4 years ago and it hasn't fallen apart yet. It has been out in the weather with soil in it. I painted it with left over wall and trim latex back then and the paint is almost peeled completely off, but the box is still intact. I've also been using cheap purchased lattice strips to grow my scarlet runner beans on for a few years now. I think they are cedar, about $3 each for a 2' x 8' strip...definitely not heavy duty. DH added trim to them for more stability. Just another option. HTH

Thank you so much! I appreciate the info.
muddy

I use unpainted pine furring strip trellises for tomatoes and they last a few years. Even then, it's only the part below ground that rots.

i built one 4 yrs ago and still using it

If wood is allowed to dry out, as in an above ground trellis, it will last a long time, even unpainted. As noted, anything in contact with the earth will rot. The only problem I see is that when wood absorbs water, then dries, then absorbs water, then dries, etc. it tends to warp. I made my trellises out of 3/4" electrical conduit with utility fencing secured to it. They work excellent, and being galvanized, they don't rust. I am an electrician, so naturally my trellises would be made of electrical material.

Joe

I finish with linseed oil. imo, very safe around all crops.

Fun trivia fact that Joe's post reminded me of.

The reason staking a vampire through the heart kills it is not because you destroyed the heart, you were originally supposed to stake it through the heart and into the ground so that the body could rot naturally.

Anything that is in contact with the earth will rot indeed.

I put up a trellis for an old grape vine with used pint two by fours and old wall lathes that lasted twenty years.

I did soak the bottom few feet of the two by fours in used motor oil for several days before I put it up though.

Thanks for all the info. My sons are coming over Sunday to build them for me for my birthday. Dicot - I think I'll try the linseed oil.
Edy, you must watch a lot of late night movies but I got the point.
thx all!

Used motor oil? I have to ask, where did you get that idea from?

People have used "used motor oil" as long as we have had motor to collect the used oil from. Linseed is better for the garden.