Bob

Thanks all, I figured there would be a lot of interest in the thermometer! The one in the pic is metal and I got it for about $20. Also there are plastic versions usually in better condition. Search ebay long enough and you'll get one reasonably. Sometimes they go for ridiculous amounts only to see the same thing come up a few weeks later for a good price.
For the $120 I paid for it I'm happy even if I get a couple of years using only in spring or fall.
Scot, good point about the windows. I guess velcro's cheap enough it might be worth adding to keep the heat in at night.
Tog, these are so cheaply made that I probably wouldn't get a bigger one. When I post my next project you'll see how I'd do it for a larger sturdier hoop house that still would be reasonable and stronger.