The containers came with lids. I'm keeping them on at all times to keep the heat in until it warms up a bit. That will also protect them from jumping out.
Sadly, 7 guppies made it through the night, and 2 made it until now. The dead ones were removed. The two left are females, one small and one even smaller. I think the reason was that they were moved from an 80F tank to a 55-60F tank in just a few hours.
The frogs are starting to croak now, so it's getting warmer. I'll try guppies again when I get more plants in the containers and the weather is warmer.
Somebody is sending me five or six large bags of anacharis that has been growing in a pond for over 40 years, as well as some lily pads, if they can find some. I'll wash them with a water hose to make sure they're free of any large pests before I add them to the containers. This should be able to cope with lots of fish and frogs.
I do have a "pond" which is about 50 gallons that has been outside for a few years, collection crap in it. No frogs or anything, just tons of duckweed and leaves. I'll be adding the duckweed to the containers too. I had a bunch of guppies and platies that were added in the spring one year, and they live through the winter of 35F nights, but of course the pond was retaining some heat from the day, so it stayed a bit cooler than the containers I have in my greenhouse right now. It's not that guppies can't survive in those conditions I guess, it's that I shocked mine when I put them in to a cold environment from a hot indoor tank.
These were just to test if guppies would live out there, which wasn't really effective because I shocked them by the move, despite acclimation. I'll probably use one container for a different kind of purebred guppy, like those sunrise ones from petsmart, the cobra ones from petco, the black moscow ones, and whatever else my local petstore has (they actually sell healthy fish).
Thanks for all the great info guys!! I'll keep you updated and post pics as things happen.