Why a Small Pond Is Worth the Digging

Few garden features repay the effort quite like a pond. Even a modest one, no bigger than a dining table, can become the busiest square metre in the garden. Within weeks of filling it, you will have water boatmen rowing about, damselflies perching on the first leaves to break the surface, and a frog or two sitting on the edge as though they have always been there.

A pond also does something a bird feeder cannot. It provides drinking and bathing water for everything from blue tits to hedgehogs, breeding habitat for amphibians, and a hunting ground for bats at dusk. In a small garden it becomes the centrepiece, a place to sit with a mug of tea and watch the surface for ripples. Best of all, it is entirely possible to build one in a weekend, with a spade, a liner and a little patience.

Choosing the Spot and the Shape

Position matters more than size. Aim for a site with a good half-day of sun, ideally sun in the morning and shade in the afternoon, which keeps the water warm without cooking it. Avoid ground beneath trees: fallen leaves rot down and feed algae, and roots have a habit of finding their way through liners.

• Level ground, so the water sits evenly and the margins do not poke above the surface.
• Somewhere visible from a kitchen window or a bench, or you will miss the best of it.
• Mildly sloping sides rather than sheer walls, so wildlife can get in and out easily.
• Away from the bottom of a slope, where garden run-off and fertiliser will wash in.

For shape, an irregular outline looks far more natural than a circle, and any spare curve gives you a shallow shelf for planting. If you already have a sunken bath, a half-barrel or an old stone sink, use it. Small containers suit smaller gardens beautifully and are far easier to manage.

Digging and Lining: Getting the Levels Right

Aim for a centre around 60 to 75 centimetres deep. That is enough to keep the water from freezing solid in a hard winter, protecting frogs and their spawn in the coldest weeks. Around the rim, dig a shelf about 20 centimetres deep and 30 centimetres wide for marginal plants, plus a second shelf at 40 to 45 centimetres if you have the room.

Line the hole with a layer of soft sand, then old carpet or builder's fleece, to cushion the liner against stones. Butyl or EPDM rubber lasts decades and is worth the cost. Dig the hole slightly larger than you think you need, lay the liner loosely, and leave at least 30 centimetres of overlap around the edge, tucked under turf or concealed with paving and pebbles.

Fill from a water butt if you can. Tap water contains nutrients and chlorine that encourage blanketweed, so rainwater is always the better choice. Let the liner settle for a day before trimming anything.

Planting a Native Community

Native plants are the difference between a puddle and a habitat. Buy from a specialist grower who does not use peat or chemical dips, and plant in baskets of hessian or open-weave mesh so roots can spread but soil stays put.

• Margins: marsh marigold, water forget-me-not, ragged robin and lesser spearwort.
• Shallow shelves: yellow flag iris, flowering rush and water mint.
• Open water: hornwort, water starwort and a small native lily such as the pygmy variety.
• Damp edges: purple loosestrife, meadowsweet and lady's smock, which will also tempt bees and hoverflies.

Aim for roughly a third of the surface covered with plants, not more. Leave open water for dragonflies to lay eggs and for birds to bathe. Resist the urge to fill every gap on day one.

Making It Safe for Wildlife

Steep, slippery sides are the main danger, particularly for hedgehogs, which swim well but cannot climb out of a vertical liner. Give them a way out: a gently sloping ramp of gravel, a stack of stones at one corner, or a piece of rough log angled into the water. Frogs, newts and even the occasional field mouse will use it too.

Add a flat stone or two just breaking the surface as perches for dragonflies, and let a few plants trail over the edge to soften it. Nearby, leave a log pile or a patch of long grass for amphibians to shelter in over winter. Skip the goldfish, which eat tadpoles and stir up sediment, and skip the pump and fountain as well: a still, plant-rich pond is cleaner and far better for wildlife.

Keeping It Thriving Through the Seasons

In spring, look for jelly-like clumps of frogspawn among the marginal plants. Do not tidy the pond until the tadpoles have grown legs and left. In summer, top up with rainwater, skim out fallen leaves with a net, and keep some longer grass around the edge for cover.

Autumn is the time to clear excess leaves before they sink, though a few are useful for tadpoles to hide in. In winter, resist the urge to smash the ice: the shock waves can kill frogs resting below. Instead, stand a pan of hot water on the surface to melt a hole and let gases escape.

Be patient with it. A new pond often looks raw for its first season, then finds its feet in its second, when the plants have filled out and the frogs have found it. By year three you will wonder how the garden ever managed without it.