>>221066Small update.
It was warm enough to paint today, so I started painting a bunch of the soda bottles of water and switching them for non-painted ones in the tunnel. I sanded them with 220 grit sandpaper first. I used black latex barn paint. It went on really thin with streaks, but after a few seconds the paint evens out and the streaks disappear. So, only a little paint is needed per bottle.
Each time I paint more bottles, the tunnel temperature, in the morning, is a little further away from the outside temperature. It was around 25° difference, now it is about 38°-39° difference. So, it can be 21F outside and 60F inside the tunnel. The hairdryer heating system also needs to run less often.
I've seen new growth on the plants and they've not dropped any flowers or fruit anymore. Those are good signs.
