James Whitfield
Why a pond earns its place in any garden
Few features do more for British wildlife than a small pond. Since the middle of the last century we have lost a huge proportion of our countryside ponds, and garden water has become genuinely important for frogs, toads and newts. You do not need anything grand. A pool roughly 1.5 metres across, with a shallow shelf and a deeper middle, will be used within weeks of filling. Common frogs often arrive first, sometimes before the water has even cleared. Smooth and palmate newts follow once plants have settled in. Add dragonflies, damselflies, water beetles and pond skaters, and you have a food chain that feeds bats, hedgehogs and garden birds as well.
A wildlife pond also sits beautifully beside a wildflower meadow or a rough grass margin, and the two habitats support each other throughout the year.
Choosing the right spot
Aim for somewhere that gets at least half a day of direct sun. Warm water means more insect life, more algae-eating invertebrates and better development of frog spawn. The south or west edge is the one amphibians will use most, so keep it open and gently sloping rather than fenced or overgrown.
Avoid the lowest corner of the garden if water drains into it from a lawn or vegetable bed. Nutrients from fertiliser or soil run-off will feed blanket weed and turn the water green. Keep clear of large deciduous trees too: fallen leaves rot down and cloud the water, and roots make digging hard work. A site beside a hedge, a rough grass strip or a wildflower patch is ideal, giving amphibians damp cover to travel through.
Digging and shaping the hole
- Mark out the shape with a hose or rope, keeping curves rather than straight lines.
- Dig the deepest section to about 60–75cm, deep enough that it will not freeze solid in a hard winter.
- Leave a shallow shelf at 15–25cm around part of the edge for marginal plants and spawning.
- Keep one side as a gentle ramp, roughly one in three or shallower, so frogs can walk in and out.
- Line with a butyl rubber liner laid over sand and old carpet or purpose-made underlay.
Fill the pond with rainwater from a water butt wherever possible. Tap water contains chlorine and nutrients, so if you must use it, let the pond stand for a few days before planting. Allow the water to settle for a week before adding anything else.
Planting for amphibians and insects
Native plants do far more for wildlife than showy garden varieties. Plant marginals in baskets or straight into the shallow shelf: marsh marigold, water forget-me-not, water mint, brooklime and creeping jenny all work well in a small pond. Add one or two oxygenators such as hornwort or water starwort to keep the water clear.
Never introduce invasive species such as parrot's feather, floating pennywort, Canadian pondweed or water fern. They spread rapidly, are difficult to remove, and can escape into the wider countryside. Avoid fish, too. Goldfish eat tadpoles and stir up silt, undoing much of the good you have done. If you want a pond for wildlife, keep it fish-free.
Around the damp edge, plant ragged robin, purple loosestrife and yellow flag iris, and let the grass grow long. Sow a little yellow rattle into the surrounding meadow to weaken the grass and let wildflowers in.
Edges, ramps and safety
The most common mistake is a pond with steep sides and nowhere to climb out. Frogs, newts, hedgehogs and beetles all drown in ponds they cannot escape. Build at least one gravel beach, a shallow shelf of stones or a piece of roughened timber sloping into the water. Stack a few logs and stones nearby to give amphibians somewhere damp to hide during the day.
If you have small children, a simple mesh cover or low fence over the first year gives peace of mind while plants establish. A pond of this size is not deep, but supervision around water is always sensible. Once the marginals have grown, the pond will look and feel like a natural part of the garden rather than a hazard.
Caring for the pond through the year
Spring is the busiest season and the one to leave alone. Frogs spawn from February onwards, and newts lay eggs singly, folded into the leaves of water plants, through spring and early summer. Do not net or move spawn, and never relocate great crested newts without expert advice, as they are protected by law.
In summer, twirl excess duckweed or blanket weed out with a stick and leave it on the pond edge for a day so creatures can crawl back. Top up with rainwater in dry spells.
In autumn, clear fallen leaves if they are smothering the pond, but leave the marginal stems and seed heads standing. They provide hollows for overwintering insects and look lovely frosted.
In winter, do not smash the ice. The shock waves can harm amphibians resting in the silt below. If you need a hole, rest a pan of hot water on the surface until it melts through. Never empty and clean a pond in spring or summer, and avoid chemicals anywhere near it. A small pond left largely to itself will settle into a balance of its own within a year or two, and reward you with frog song on mild February evenings for many years after.
