I sink my lillys every winter and I've seen green frogs hibernate on top of the plants. I think these are the frogs that lost the lottery as most prefer to crawl into the folds of my pond liner.

I think the area they choose to hibernate doesn't matter as long as the water in that area doesn't freeze.

Be careful in the spring. If the frogs come out of hibernation too early they can die. I postpone my spring cleanup until I'm sure its warm enough for the frogs.

I've never found a dead frog in my pond, so I guess they know what they are doing.

Not all species of frogs hibernate the same way. He may have different species frequenting his property than you have and his pond may be set up differently than yours. It's been my experience that merely keeping the water from freezing in the area you provide for them to hibernate isn't enough particularly in zones 5/6 and below.

The basket of soil at the bottom of the pond has worked for a few but failed for most in the colder zones. Many reasons for the failures. The material at the bottom of ponds isn't exclusively soil per se but more so an accumulation of many different types of organic materials. These natural layers provide optimal protection combined with the lower temps of a natural pond bottom being in the 40°F range or rather the 5°C range for you. You could try the basket of soil combined with stock tank heaters with thermostats to maintain temps in the appropriate range at the bottom of your pond and that might work. I don't believe the basket of soil alone is going to be enough to overwinter green and leopard frogs but there may be those who would disagree.

Thanks for the info. I brought these frogs home from the north where it gets much colder and the water freezes so thick that you can drive on it without problems. But I guess being a lake and being much deeper, it must be warmer at the bottom compared to a backyard pond.
I will set up the basket with about 4-5" of soil and then layer the rest with leaves (I'll use the large maple leaves once my tree starts dropping its leaves). I might have to put a small rock or two on the top to hold down the leaves This will then look more like the shallow area where I got them from (muck and maple leaves on the bottom), except mine will be in a 8" square aquatic basket.
I hope that by intentionally adding the leaves it doesn't mess up the water quality, as in the fall I'm always trying to remove all the leaves possible before the pond freezes over.

I'm not sure when I need to start setting this up. My trees aren't losing their leaves yet. Do I need to do this before I trim my plants and sink the them (I think I did that around the end of October?). In other words, when do the frogs start to swim down to hibernate?

Sink items the frog can wedge under (overturned clay flower pots, 2' sections of plastic corrugated drainage pipe weighted down with a brick or two. Stuff like that. They do like the folds in liners but they need to go to a fold that is deep where the water does not freeze, not a fold that is just under the surface. The folds near the surface in my pond are taped shut, but that was not that hard as I have a rectangular pond with a grand total of 4 folds (one big one in each corner).

A bunch of nooks and crannies near the surface might not be great if they are selected by the frogs.

I thought Webfeeet said frogs 'breathe' through their skin when resting on the bottom of ponds and don't bury themselves, and in fact, if nothing is down there they will just sink to the bottom. Since they have no air in their lungs they won't float so it makes sense. I'm thinking they like to wedge in places is so they can be hidden and it is safer from being dislodged by currents or whatnot in their natural environment. They don't know the pond is not natural.

A 500 gallon per hour pump mounted just under the surface of the pond will keep open water. I would not put it in an area you can't reach however. If you loose power you might want a generator on hand.

BTW - fish like those short sections of pipe as well is those large clay strawberry pots sitting on their sides on the bottom, but if you use one hand-sand the edges of all the holes as they are sharp.

Based on a single winter's experience, I'd agree with Laurazone5. I sunk a cat litter full of clay to the bottom last winter, and none of the frogs went into it.

Also, none re-appeared in the spring, either dead or alive, so I'm not sure what happened.

Thanks for the interesting info. Somehow I had gotten the idea that frogs bury into the mud. I'll sink some old pipes and still try the basket if I have room. Plus I leave the koi castle in, but I notice that many times the fish like to hide between the baskets.

Good tip about taping up the folds.. I have lots near the surface due to the peanut shape of my pond. What do you use to tape them up... Is there some kind of proper fish safe tape that is used specificially for pond liners? Or can I use duct tape, black electrical tape, or plain packaging tape?

By the way, I'll keep my pond open at first with a bubbler and decier, but as it gets more frozen, then I use the decier only. Using the two together last year in the middle of winter caused me alot of grief as the bubbler forced water out all over deicer (even though they were 3 feet apart) and almost froze down the deicer. Most of my fish survive each year, so they must be getting enough oxygen, so I would think the frogs should be okay then too.

I taped down my liner corners at installation when the liner was dry using 6" wide pond liner tape. It is that tape people use when they want to put two pieces of liner together. I had a roll of it. I think I bought it at Unit Liner on-line but can't swear by that now.

Thanks. That is the safest way to go, besides duct tape would have looked quite ugly.