/johnny-- That's just PVC piping. It's the frame for frost protection plastic, and summer shade cloth. We just pounded some rebar into each corner of the square and placed the ends of the tube in each one. Works good.
Growing tomatillos is pretty much like growing tomatoes. You need two of them to cross-pollinate, but they're hearty and fast growing, just like tomatoes. Those are them in the big white containers. We did get these from the nursery as little seedlings (because it was late) but next year we'll try different kinds from seed.
I had to deal with some PEX today, and the piece I cut off was curved like that.... I may do some experimenting to see how that holds up in the sunlight. I need hoop row covers for next year, and they gotta be cheap. I already have a roll of PEX in hand... Time to McGyver something to work...
/johnny