Thanks for the tips TC
Your right anout the depth. I was thinking of lettuce,spiniach,ect. in the winter months....hadn't thought about summer months yet.(?) Tomato roots do go pretty deep and wide...

The 'conduit' fittings will work with pvc 'water' pipe. I'm using the pvc 'conduit' fittings because, the threads are 'straight' on them. So, I can either screw a lock nut or a female adapter 'all the way' to the shoulder of the male adapter.

The threads on 'plumbing/water' fittings have a slight taper. If you try to put a 'plumbing/water' male and female adapters together, I doubt they would go all the way together.

I too, wonder about the safety of the gray pvc 'conduit'....I'm just using the 'fittings.' The pipe runs will be plumbing pvc.

The gray pvc (conduit) has a UV rating, the white pvc doesnt...go figure.