Creating a Wildlife Pond in a Small Back Garden

A Pond the Size of a Barrel Still Counts

You do not need a paddock, a liner the size of a tennis court or a digger on the lawn. A half-barrel, an old sink or a pre-formed basin sunk into a border can hold everything a small garden needs: a place where frogs gather, damselflies dry their wings and hedgehogs stop for a drink on their evening rounds. In the river valley, where damp air and heavy clay already suit wildlife, even a modest pond becomes a hub within a season or two.

The trick is not size but structure. Water needs somewhere shallow to warm up, somewhere deeper to stay cool, plenty of native plants, and an easy way out for anything that falls in. Get those four things right and the rest looks after itself.

Choosing the Spot and the Container

Aim for somewhere that gets sun for part of the day but is not baked from dawn to dusk. Around five or six hours of light encourages water lilies and marginal flowers to bloom, while a little afternoon shade keeps the water cooler and discourages blanketweed. Avoid sitting it directly beneath a tree or hedge, where fallen leaves will rot and roots may pierce the liner.

For a barrel or tub, 60 to 80cm across and at least 40cm deep is ideal. Depth matters: shallower water heats and cools rapidly, which stresses everything living in it. If you are sinking a pre-formed pond into the ground, a depth of 45 to 60cm is plenty for a garden this size, and it keeps the build safely shallow where young children are about.

• Line the barrel with a butyl or flexible liner, or choose one already watertight and safe for plants.
• Add a layer of aquatic compost in the bottom, then a thin cap of gravel to stop it clouding.
• Fill with rainwater from a butt wherever possible. Tap water contains nutrients and chlorine that fuel algae.
• Leave the water to settle for a week before planting, so it reaches ambient temperature.

Plants That Do the Work

Native plants are the difference between a tub of green water and a living pond. They provide cover for tadpoles, landing pads for insects and stems for emerging dragonfly larvae to climb. Build the planting in layers.

• Oxygenators such as hornwort and water starwort, kept submerged, compete with algae and shelter small creatures.
• Marginals around the edge: marsh marigold, water forget-me-not, brooklime, lesser spearwort and ragged robin. These give the pond a soft, natural fringe.
• Floaters and lilies: a single small water lily such as a pygmy variety, plus native frogbit, which shades the surface and reduces algae without smothering the pond.

Please steer clear of the thugs. Floating pennywort, parrot's feather, water fern and New Zealand pygmyweed are invasive and illegal to plant in the wild, and they will overwhelm a small pond in weeks. If a neighbour offers you a handful of something green and unknown, say thank you and leave it in the pot.

A Gentle Slope for Frogs, Hedgehogs and Everything Else

This is the single most important design detail in a small pond, and the easiest to forget. Anything that enters the water needs a way out that is not a vertical wall.

• Create a pebble beach at one end, sloping from just below the water surface up onto dry ground. Line it with smooth stones so amphibians can clamber out.
• Add a rough wooden ramp from the water to the rim, with a few grooves or a piece of bark attached for grip. This is a lifeline for hedgehogs, which swim well but drown when they cannot climb out.
• Plant right up to the edge, leaving one open stretch of water for drinking and for dragonflies to patrol.

If you have young children, a shallow shelf and a firm rim are sensible, along with the usual supervision. A garden pond of this depth is far less of a hazard than a steep-sided one, and the wildlife value is enormous.

What Will Arrive, and When

Patience pays. Nothing much happens in the first fortnight, and then it happens all at once.

• Within weeks: pond skaters, water boatmen, diving beetles and the first midges and mosquitoes, which are food rather than a problem.
• By the first spring: frogs, arriving from nearby ditches and damp corners, with spawn in February or March in most valley gardens.
• Through the summer: damselflies first, then dragonflies, drawn by the plants and the open water.
• In autumn and winter: hedgehogs, birds and even badgers coming to drink. A shallow pebble edge makes a safe watering hole.

Never move frogspawn or adult amphibians in from elsewhere. Disease and invasive plants travel with them, and your pond will fill naturally given a little time.

Keeping It Going Through the Year

A wildlife pond is not a swimming pool. The goal is a bit of mess, and tidying too hard does real harm.

• Top up with rainwater in dry spells, never tap water if you can help it.
• Leave seed heads and stems standing over winter for insects and shelter, and cut back in late February.
• Remove fallen leaves with a net in autumn, but leave anything that has already sunk for the creatures living in the silt.
• Never empty and scrub the pond. You would be throwing away the entire community in one afternoon.

Pull out excess blanketweed by hand in spring, using a stick to twist it like candyfloss, and leave it on the edge for a day so anything caught up can crawl back in. Skip chemicals entirely, and keep fish out; they eat tadpoles, larvae and just about everything else worth having.

Do these small things and your half-barrel becomes the liveliest patch of ground in the garden, humming on a summer evening and humming with it right through to the first frost.