Should I melt ice on garden pond?

[cwilk]

Hi all,

My small garden pond (approx 5x3 foot, 3 foot deep at middle but shallow edges) has been frozen over for the last couple of weeks. There has been lots of frogs and newts in over the summer. Will they be OK under the ice, will there be enough oxygen in the water for them? I am loth to break the ice as I imagine the shockwaves would be harmful but would it be worth pouring some warm water in one corner to melt it.? I wondered if the weeds and leaves under the water would be going putrid, or will it be too cold for that? Any advice folks?

[Fireweed]

We have a little pond - even smaller than yours.

We always have something floating in the pond during the winter - we have one quite naturalistic plastic duck and two garish little yellow plastic ducks (I am sure the latter are really off-putting to wildlife but they weren't my purchase!) The point is that something floating stops the pond freezing over entirely. I pull out the ducks when it is frozen and try to pull away some of the ice (not smash it).

I have used a little hot water but I am really not sure this is advisable, so I would be interested to see what others say to your query.

Opening up the ice is definitely vital. We have found that out in a very real way this winter - two dead frogs! We weren't as diligent about opening up the ice as we should have been and that was the result.

[BloomingMarvellous]

Our pond has frozen over several times and we've been a little bit worried on how the Fish and all the other things that come with a pond have been coping through this period of freezing then thawing just to re-freeze again.

Well we don't have to worry anymore as yesterday the Fish popped out for a couple of hours when the Sun came out and warmed the water. We haven't done anything to prevent the pond from freezing over for the past few years now and suffered little consequence.

[Lancashire Lad]

Concensus is usually to float something like a small plastic football on the pond, which in theory makes it more difficult for a full covering of ice to form.

If the pond does get iced over, a pan of boiling water stood on the ice will melt a hole through, without sending shock waves into the water.

Regards
Mike.

[kiltoncomp]

the only time our pond froze over completely(some years ago now)
i melted a hole in the ice with a saucepan and boiling water, and then pumped out some water to leave a gap between the water and the ice,(about 1 or 2 inches)
it lets out any noxious gases that developed in the water and also semed to insulate the whole pond, and although the ice did not melt, the water below did not freeze again, while that cold snap persisted.

[Cotham Marble]

Originally Posted by cwilk

Hi all,

My small garden pond (approx 5x3 foot, 3 foot deep at middle but shallow edges) has been frozen over for the last couple of weeks. There has been lots of frogs and newts in over the summer. Will they be OK under the ice, will there be enough oxygen in the water for them? I am loth to break the ice as I imagine the shockwaves would be harmful but would it be worth pouring some warm water in one corner to melt it.? I wondered if the weeds and leaves under the water would be going putrid, or will it be too cold for that? Any advice folks?

Ponds were freezing over long before humans were around to break the ice, so unless there were some other habitual ice breaker I think we can assume bottom dwelling wildlife can survive without intervention - fish though may be more endagered given that small isolated ponds are not their usual habitat.

Ice melting is more important for birds but providing one or more small plastic bowls which can be replenished with unfrozen water each day is a more practical option than breaking up pond ice. It's worth remembering that hot water freezes more quickly than cold so the boiling water option may be both less effective and less ecological than emptying the ice and refilling using water from the cold tap.

CM

[Jim Ford]

Originally Posted by kiltoncomp

the only time our pond froze over completely(some years ago now)
i melted a hole in the ice with a saucepan and boiling water, and then pumped out some water to leave a gap between the water and the ice,(about 1 or 2 inches)
it lets out any noxious gases that developed in the water and also semed to insulate the whole pond, and although the ice did not melt, the water below did not freeze again, while that cold snap persisted.

That's a very good idea!

Jim

[Cotham Marble]

Originally Posted by kiltoncomp

the only time our pond froze over completely(some years ago now)
i melted a hole in the ice with a saucepan and boiling water, and then pumped out some water to leave a gap between the water and the ice,(about 1 or 2 inches)
it lets out any noxious gases that developed in the water and also semed to insulate the whole pond, and although the ice did not melt, the water below did not freeze again, while that cold snap persisted.

I'm puzzled by the idea that noxious gasses might build up. Ice is a fairly permeable material and it is only at great thicknesses where atmospheric sealing would occur. And unless the body of water is very deep, the cold will have slowed down all bacterial activity so that putrefaction will be largely on hold. In a temperate climate a frozen pond is a natural environment, unless it's supporting some tender species of plant or animal then there should be no need for intervention. - Or I have I missed something ?

CM

[Fireweed]

Froglife give this advice:

"Frogs often hibernate at the bottom of ponds and in order to stop them suffocating if it ices over you need to create a hole in the ice. The best way to do this is to leave a football or other floating object in the pond which can be removed to leave a hole if it freezes. If you have not done this then just use a pan of hot water placed on the ice to melt a hole - never pour on hot water, chemicals or salt or attempt to smash the ice as this can damage not just the pond life but the pond liner as well. If we are predicted cold weather in the spring, after the amphibians have laid their eggs, you might want to think about protecting the spawn."

Froglife say that decomposing plants can produce noxious gases under the ice. This reduces oxygen in the water and fresh oxygen can't get in because of the ice. If this goes on for long enough this can kill frogs. They will be found floating on top, bloated and pallid.

[camo]

Originally Posted by Cotham Marble

I'm puzzled by the idea that noxious gasses might build up. Ice is a fairly permeable material and it is only at great thicknesses where atmospheric sealing would occur. And unless the body of water is very deep, the cold will have slowed down all bacterial activity so that putrefaction will be largely on hold. In a temperate climate a frozen pond is a natural environment, unless it's supporting some tender species of plant or animal then there should be no need for intervention. - Or I have I missed something ?

CM

I think both Cotham and Kiltoncomp raise important points. The ability for an artificial pond to sustain winter depends on the capacity to retain enough oxygen within the water and a balance nitrite/nitrate/ammonium level.

I like KC idea as the action increases the surface water area, but you are in danger of reducing the mass of oxygen carrying water and subsequent freezing and lowering may have a cumulative harmful effect. Cotham introduces the importance of depth and the slowing down of bacterial and fish activity. I do not know about the permability of ice but certainly it is common to see bubbles under the ice so clearly this must be a slow process. Cotham refers to natural ponds freezing over and yes it is correct but for most members their pond will be artificial and comparitively shallow with a high density of life which requires more involvement.

I think the advice should be if contemplating a pond understand the effect of freezing, make it deep enough and do not overload the fish. Where you have a shallow pond containing life Fireweeds froglife advice is excellant.

Roy