Freshwater primer · Temperate gardens
Twenty centimetres of water separate a marsh marigold from a water lily, a hunting newt from a drifting water flea. Cut the basin so that all four bands exist, and the rest arrives on its own.
Silt and leaf litter — the pond's larder
Guide 01 · Construction Cut and liner
Choose light over size. Three or four square metres in the open will hold more life than twice that in shade. Aim for five or six hours of summer sun, and keep clear of overhanging deciduous branches — a pond under a sycamore spends its winter digesting leaves.
Profile matters more than volume. Cut a wide shelf at twenty to thirty centimetres for marginal plants, drop to sixty or eighty in one corner so the water cannot freeze through or overheat, and run one side out onto the grass as a shallow beach — the front door that frogs, hedgehogs and fledglings all use, and the part most often left out.
Line the hole with five centimetres of sifted sand or old carpet, then fold the liner rather than cutting it. Fill from a water butt if you can — tap water carries the nitrate and phosphate that feed a first-summer algal bloom. Then leave it alone.
Butyl or EPDM sheet lasts decades, folds into corners and can be patched. Preformed shells are quick, but their moulded profile almost never includes a usable beach. Concrete cracks with frost and leaches lime into new water.
No fish in a wildlife pond: they eat tadpoles and invertebrates. No spawn, silt or plants lifted from other ponds — that is how ranavirus, chytrid fungus and invasive weed fragments travel. Avoid New Zealand pigmyweed, parrot's feather, floating pennywort and curly waterweed.
Guide 02 · Maintenance Twelve months
Most pond work is deciding not to do something. These are the four windows that matter.
Do nothing loudly. Frogspawn arrives in clumps from late February in mild districts, toads follow with strings wound through submerged stems, and newts court a few weeks later. Top up with rainwater, not tap. If blanketweed appears, twirl it out on a stick and leave the heap on the bank overnight so its passengers can crawl back.
Watch the level and the light. A small pond can drop several centimetres in a hot week; refill in small doses. Aim for floating leaves over a third to a half of the surface — shade suppresses algae and gives damselflies a landing stage. Skip chemical treatments; they take the invertebrates with the weed.
This is the maintenance window. Net fallen leaves before they sink, and if silt has built past a third of the depth, scoop some out now, while the amphibians are back on land. Leave every scoop on the edge for a day. Cut back marginals, but leave some hollow stems standing.
Leave it be. A few days of ice is harmless; weeks of ice over rotting leaves is not, because decay strips the oxygen from the water beneath. Melt a hole with a pan of hot water — never hammer the ice, which carries the shock through. Frogs may be down in the silt, taking oxygen through their skin.
Guide 03 · EcologyFive tiers
Almost nothing in a garden pond eats a living plant. The energy moving through it arrives as dead leaves, pollen and the brown film of algae and bacteria coating every submerged surface. Shredders chew the litter into fragments, snails rasp the film off stones, and water fleas strain algae from open water — which is why a new pond's pea-green phase usually clears by itself.
Above that sits a tier of hunters. Dragonfly larvae wait in the silt and shoot out a hinged jaw. Great diving beetles and their sickle-jawed larvae take tadpoles. Backswimmers row upside down beneath the surface film, while the lesser water boatman below them is a mostly vegetarian lookalike. Newts, frogs and young toads feed on that tier, and are fed on in turn by grass snakes, herons and blackbirds.
Nothing here has to be introduced. Flying insects arrive in the first season; amphibians in the second or third.
Field index24 entries
Species common in temperate gardens across Europe and comparable climates. Check which of them are native, invasive or restricted where you live before buying or planting.
Showing all 24 entries.
Earliest nectar at the water's edge; dies back by midsummer.
Frayed pink petals on damp ground; worked hard by long-tongued bees.
A long bee season in its native Europe; a serious invasive in North America.
Drinks at the beach edge and drowns where the sides are sheer.
Works the air at dusk for midges and caddis rising off the water.
Spreads by runners; hoverflies and small bees crowd the flower heads.
Newts fold their eggs one at a time into the soft leaves.
Sprawls across the waterline and hides the cut edge of the liner.
Yellow buttercup flowers; well behaved where its larger relatives are not.
Handsome and vigorous — give it a basket, and skip it where non-native.
Spawns in clumps in the shallows, then spends most of the year on land.
Courts in spring; the larvae keep feathered gills through the summer.
Grazes biofilm from stems and surfaces at intervals to refill its lung.
Free-floating rosettes that sink to the bed as winter buds.
Floating leaves give damselflies a perch and shade the water below.
Two leaf shapes at once — threadlike below, lobed at the surface.
Lays strings of spawn wound through stems; prefers deeper water than frogs.
Pairs stay linked in tandem while laying into floating leaves.
Carries an air store under its wing cases; the larvae take tadpoles.
Rows upside down under the film — a predator, unlike the water boatman below.
Rootless oxygenator that overwinters as shoots resting on the silt.
Anchors on stone and shelters the smallest invertebrates.
Needs 60 cm and room to spread; use a dwarf cultivar in a small pond.
Hunts from the silt for months, then climbs a stem to emerge.