Autumn and winter at the pond
Winter pond care
What should you do with a pond in winter? Never smash the ice: the RHS warns the shock waves can harm fish, so hold a pan of hot water on it to melt a hole. Net the pond against falling leaves in autumn, stop feeding fish once cold weather arrives, and keep a fish pond's pump running near the surface.
Pond jobs month by month, northern hemisphere
January Winter
- Never crack the ice: hold a pan of hot water on it until it melts a hole. RHS
- Keep koi and goldfish ponds from freezing over with a pond heater, an air pump or floats. RHS
- Wildlife ponds with few or no fish usually don't need a hole in the ice, unless rotting leaves have built up. RHS
- If it is safe, brush snow off the ice so light reaches the water; don't go out on the ice. RHS
- Check the water level and top up any big drop; hard frosts can damage a liner. RHS
- Rake out fallen leaves, or shake them off the netting. RHS
February Winter
- Dig a new pond now, so the spring rain helps to fill it. RHS
- Shape gentle slopes from the bank into the water, and give steep-sided ponds a wildlife ramp. RHS
- Frogspawn can appear from January onwards, first in the west and south-west. FHT
- Fit a mesh grille if young children use the garden, keeping a way in and out for wildlife. RHS
March Spring
- Take the leaf net off and store it in a shed, not at the pond edge where hedgehogs can get caught. RHS
- Start feeding goldfish and koi again, little and often. RHS
- Don't move frog, toad or newt spawn between ponds: it can spread disease and invasive weeds. RHS
- Cut back old marginal growth and leave it by the pond for 48 hours so creatures can return. RHS
- Remove pond heaters as it warms, clean the filter and check pumps and water features. RHS
April Spring
- Divide or trim crowded marginal and bog plants; split waterlilies as new growth starts. RHS
- Feed waterlilies that flowered poorly with slow-release aquatic fertiliser tablets. RHS
- Green water in spring is normal; if it lasts more than a few weeks, add floating and oxygenating plants. RHS
- Newts and toads lay eggs from early spring; newts wrap each egg in a leaf. FHT
May Spring
- You can still add new pond plants; add fish only once new plants have settled. RHS
- Don't add goldfish to a wildlife pond: they eat frogspawn. RHS
- Twirl blanket weed out on a stick and skim off duckweed; leave it by the pond for 48 hours. RHS
June Summer
- Shade a third to a half of the surface with waterlilies to help keep algae down. RHS
- Top up with rainwater from a water butt rather than tap water. RHS
- Leave long grass or planting along one side as cover for young frogs and newts. RHS
- Damselflies emerge, then dragonflies; frog tadpoles turn into froglets and leave the pond. FHT
July Summer
- Keep pumps and fountains running on sultry nights, when oxygen levels drop. RHS
- Add upright marginals such as irises for dragonfly larvae to climb out on. RHS
- Remove dead leaves and spent flowers from waterlilies; keep skimming weed. RHS
August Summer
- In hot, humid weather leave fountains running overnight. RHS
- Top up low ponds, and cut back faded flowers and yellow leaves of marginals. RHS
September Autumn
- Cover the pond with netting if a lot of leaves fall on it. RHS
- Top up fish ponds only; wildlife ponds can wait for the autumn rain. RHS
- If the pond needs desilting, clear only half of it so wildlife can recolonise. RHS
- Thin crowded oxygenators and cut back overgrown marginals. RHS
October Autumn
- Put nets over ponds to keep autumn leaves out. RHS
- Leave marginals that are still standing until late winter, as shelter for overwintering insects. RHS
- Take out fountain pumps and removable lights, clean them and store them for winter. RHS
- Lift tender water plants and keep them frost-free until late spring. RHS
November Autumn
- Stop feeding fish once cold weather arrives. RHS
- Rake out fallen leaves, or shake them off the netting. RHS
- Remove the last of the dead foliage, and any barley straw used against algae. RHS
- Cut long grass around the pond now: most amphibians have left the water. RHS
December Winter
- Use air pumps, floats or pond heaters to stop fish ponds freezing over. RHS
- If it freezes, hold a pan of hot water on the ice to melt a hole; don't crack it. RHS
- Keep raking out leaves or shaking them off the netting; December is a good month to fix leaks. RHS
- Under the ice, insect larvae overwinter, and some frogs and newts hibernate in the water. FHT
When the pond freezes
Do
- Melt a hole by holding or standing a saucepan of hot water on the ice (RHS, RSPCA).
- Keep a hole open in a fish pond with a floating pond heater or de-icer, an air pump or bubble fountain, or floats on the surface (RHS, RSPCA, OATA). A floating ball delays freezing, but don't tempt children onto the ice (RHS).
- If you run a pump to keep a hole open, stand it in a shallow area, so it doesn't stir up all the water (Tetra).
- If it's safe, brush snow off the ice to let light reach the plants (RHS, FHT).
Don't
- Don't smash, crack or hit the ice: “Never smash the ice, as the shock waves can harm fish” (RHS).
- Don't pour boiling water straight onto the pond; it can harm or kill fish (RSPCA).
- Never use antifreeze or salt to thaw a pond or birdbath (RSPCA).
- Don't walk on a frozen pond (Tetra; FHT).
Why a hole?
- A hole lets gases escape and stops the water going stagnant (RSPCA).
- The Freshwater Habitats Trust adds that a hole makes little difference to oxygen, but helps air-breathing creatures and gives birds a drink; if fish or amphibians are under ice for more than 2–3 days, run a pump or fountain.
- Wildlife ponds with few or no fish usually don't need a hole, unless rotting leaves have built up (RHS).
Leaf netting
When
- September: net the pond if a lot of leaves fall on it; a few don't matter (RHS).
- October: put nets over ponds to keep autumn leaves out (RHS).
- November to January: shake the leaves off the net, or rake them out (RHS).
- March: take the net off (RHS). In the southern hemisphere, shift each month by six.
How
- Through the winter, shake off the leaves caught on the net, or rake out any that get into the water (RHS).
- Store it in a shed or garage afterwards, not at the pond edge, where hedgehogs and other wildlife can get caught (RHS).
Wildlife ponds
- A few leaves feed and shelter caddis fly larvae; there's no harm removing some, but a wildlife pond doesn't need regular clearing out (FHT).
- Leave marginals that are still standing until late winter, as shelter for overwintering insects (RHS).
Pumps and filters in winter
Fish ponds
- Keep the filter pump running if you have fish: the filter bacteria stay alive, and water quality is better year-round (Pondkeeper; Hozelock pond advice).
- Raise the pump into the top third of the pond, so only the upper water circulates and the bottom stays warmer for the fish (Hozelock pond advice; Pondkeeper).
- Circulating water with a pump raises oxygen levels for fish and amphibians (RHS).
UV clarifiers and filters
- Switch off, drain and remove a UV clarifier if there's any risk of freezing: ice inside it cracks the quartz tube (Hozelock pond advice).
- Don't run or leave a filter unit in freezing conditions (Hozelock filter instructions).
Fountains and stored pumps
- In autumn, take out fountain pumps and removable lights, clean them and store them (RHS).
- Clean, dry and store a filter unit somewhere frost-free when it is not in use (Hozelock); keep a stored pump in a bucket of water so the seals stay lubricated (Aquascape).
How to use the pond calendar
Each month lists the jobs the RHS gives for garden ponds, with wildlife notes from the Freshwater Habitats Trust's pond calendar. Jobs about ice, leaf nets and fish feeding are in bold. The month your device's clock says it is gets a “This month” label.
The jobs are written for the northern hemisphere. Choose Southern and each job moves six months: seasons are reversed in the southern hemisphere but start on the same dates, so January's frost jobs fall in July and October's leaf netting in April.
Timings follow the weather more than the calendar: stop feeding fish when the water turns cold, whatever the date, and net the pond when the leaves start to fall.
Sources
- RHS, monthly pond advice: January, February, March, April, May, June, July, August, September, October, November, December; and Pond care: maintenance tips (never smash the ice; hot pan, bubble fountain or pump; floating ball).
- Freshwater Habitats Trust and partners, Creating Garden Ponds for Wildlife (2023): the pond calendar; ice and oxygen; leaves and caddis flies.
- RSPCA, Caring for pet fish in winter: don't break the ice; a saucepan of hot water, never boiling water; a floating pond heater, de-icer or aerator for gas exchange; never antifreeze or salt.
- Ornamental Aquatic Trade Association, How to look after pond fish (September 2022): a pond heater or floating device so the surface isn't sealed with ice.
- Tetra, The right way to care for your pond: a pump or aerator in a shallow area; don't hack at thick ice or walk on it.
- Hozelock pond advice, Winter (Hozelock Cyprio technical pages, reproduced by TLC Direct): the pump in the top third of the pond; drain and remove the UV clarifier if there's a risk of freezing. Hozelock, Ecopower+ instructions: store frost-free when not in use; don't operate in freezing conditions.
- Pondkeeper, Should you keep your pond pump running in winter?: keep it running with fish; raise it from the bottom; filter bacteria survive.
- Aquascape, Pond Builder's Bible, chapter 7: store a removed pump in a bucket of water to keep the seals lubricated.
- NOAA National Centers for Environmental Information, Meteorological versus astronomical seasons: the seasons are reversed in the southern hemisphere but begin on the same dates.
Winter pond questions
Should I break the ice on my pond?
No. The RHS says never smash the ice, as the shock waves can harm fish. Hold a saucepan of hot water on it until it melts a hole.
When should I put a net over my pond?
From September or October, as the leaves start to fall, and take it off in March. Shake the leaves off regularly over the winter.
Should I turn my pond pump off in winter?
Not in a fish pond: keep the filter running, with the pump raised into the top third of the water. Fountain pumps can come out, be cleaned and be stored.
Can I use salt or antifreeze to stop my pond freezing?
Never. The RSPCA warns against antifreeze and salt; use a pond heater, de-icer or air pump instead.
When should I stop feeding pond fish?
Once cold weather arrives: the RHS lists it among its November jobs. OATA adds that below 8 °C it may be better not to feed at all.