Pond

Building a frog pond is just what we thought it would be: dig a hole 2 or 3 feet deep and line it with a plastic sheet. It should be located in a partial shade area - which ours would be.

Attracting frogs requires: a pond with one ore more tapered edges (so they can get in and out), floating plants (hardy water lily is a perennial), rocks, and more plants around the pond to provide shelter for frogs and attract insects.

Ponds should be cleaned at least once a year to ensure the water has enough oxygen.

Not too bad so far. The problem is the winter...

If the pond freezes the frogs will die from lack of oxygen. We'd need to make sure there is always a hole on the ice and that they have a few places to hide under at the bottom of the pond. We'd also have to provide shelter for frogs that overwinter in land: tree trunks, piles of leaves, mulch, compost, clay pots, etc. And then there are the predators: snakes, raccoons, cats, etc. I read a bunch of blog posts about frogs being decimated by lack of oxygen (frozen water) and by predators (snakes).

One possibility would be to scoop up the frogs just before the first frost and move them to the greenhouse for the winter. But we'd have to provide them with water (for the ones that hibernate under water) and shelter (for the ones that hibernate on the ground under stuff).

Here's a list of cold hardy plants for ponds: http://www.pondplantgirl.com/coldclimate.htm

I would love a pond. But I dislike dead animals even more than I dislike dead plants. So we should only do it of we can find a way to keep them alive with low maintenance. We know we won't be running to the pond with a pot of hot water each time it's about to freeze :)