Use an exterior, water-based paint and it will be safe for your plants and the environment.

is it safe? Do I have to worry about contamination of any kind?

Yes it is safe and no you don't have to worry about contamination. Plants don't absorb paint nor any of the things in the paint.

Or you can just buy the dark gray PVC and not worry about it.

Dave

Thanks guys!

I built a fruit cage out of white PVC last year to go over my six blueberry bushes in my front yard. The white was just so stark and seemed to glow from a distance, that I painted it black this winter. You may or may not know that there is a special spray paint specifically for PVC. It was easy to work with and the black is far less obvious. Just an FYI.

I have (unpainted) white one-inch diameter pipe PVC trellises that have been out in the bright sun for ten years, and they don't seem to be degrading, nor do they even show any of the "UV discoloration" that supposedly points to UV exposure. I wonder if this is more an issue for thin-walled pipe. In any case, the effects of UV on PVC are restricted to the outer skin, and doesn't affect the strength of thick-walled pipe. See attached link.

Here is a link that might be useful: UV Exposure Has No Practical Effect on PVC Pipe

1) PVC is not that expensive to spend money and time to paint it in orde to, supposedly, extend its service life:

2) Grey color ( as used for electrical wiring) is supposed to be more tolerant of UV light.

3) You heard it first hand from Dan, in Tx, Heat zone 10 that even the white PVC is much tolerant of UV light.

I frankly never considered UV degradation when I made my trellising, but it looks like the importance of PVC UV degradation may be commonly misinterpreted. To the extent it's about surface degradation, it's probably a lot more important for thin-wall applications, like flexible hoses and hoop-construction. For thin-walled pipe, surface is all there is.

Now, although PVC is not structurally compromised by UV, I understand that the impact resistance may suffer. I'm not whacking my trellises with anything, so I think that's probably irrelevant.

But cosmetically, yes, I'd rather have dark colored PVC.