With the first round of sub-zero temperatures around the country this year, we’re gearing up to receive enquiries about ponds freezing, and how this will affect amphibians. Here, we’ll try to answer some of those questions to dispel those winter worries.


Frogspawn can be affected by cold weather. If a layer of ice forms over the surface of the spawn it may die, but the eggs at the bottom of the clump still have a chance of survival. Newt eggs and toad spawn tend to be more protected from frosts as they are laid slightly later in the year and deeper underwater. Sometimes icy weather can interrupt spawning, in which case a second batch of frogspawn may turn up in your pond once the cold weather subsides.


In Britain, amphibians largely hibernate on land but some adult male common frogs may lie dormant at the bottom of ponds in winter. You can read more about this in our blog “Where do frogs go in winter?” and in our Hibernation FAQs. Occasionally, in particularly icy spells, frogs can die of 'winterkill', where toxic gases (released in the pond through natural decomposition of dead leaves) cannot escape from the pond due to the layer of ice. Though this can be upsetting, this phenomenon is natural and will only affect a very small percentage of the local frog population. Read more about winterkill on the Garden Wildlife Health website.

Amphibians are adapted to “breathe” through their skin. If there is enough oxygen in the water, they can survive for long periods beneath the ice. A common solution is to create a hole in the ice to allow gas exchange with the air. However, research suggests that this may not be effective, and growth of plants and green algae may be more helpful. Pond plants and algae oxygenate the water, even under ice. While a hole in the ice won't make much difference to the oxygen in the pond, it may help air breathing creatures swim to the surface for air (such as smooth newts). It will also give other wildlife somewhere to drink.

What you can do

Clearing snow from the surface of a frozen pond may help, letting light enter and increasing oxygen production from submerged plants and algae. Never pour hot water on to the ice or use chemicals or salt. Similarly, do not smash the ice as this can damage pond liners and plants. The best way to create a hole in the ice is to leave a ball or other floating object in the pond and remove it to leave a hole after freezing. You can also help by ensuring there are suitable sheltered places on land where amphibians can spend the winter undisturbed. 

Our Habitat Management Handbooks give advice for reserve managers, and both our “Dragons in your Garden” leaflet and the “Creating garden ponds for wildlife” leaflet should be useful for those with a backyard. Finally, please be very careful around frozen ponds. Although it looks solid, ice can be deceptively thin - it won’t hold much weight. Cleaning snow from the ice will make the pond more visible to anyone nearby.


Our native amphibians are well adapted for our weather conditions and although this very cold weather can be concerning they will muddle through and will soon be taking advantage of spring sunshine and spawning once more.