Why a pond beats almost anything else you can do

A pond is the closest thing to a wildlife magnet you can build in a British garden. Water is scarce in the wider landscape, so anything that holds it — even a washing-up bowl sunk into a border — draws in creatures from a surprising distance. Within a season you might see common frogs, smooth newts, damselflies and dragonflies, plus a steady stream of birds visiting to drink and bathe. Hedgehogs will stop by for a drink, and bats will hunt insects over the surface at dusk.

Happily, it doesn't need to be big, expensive or immaculate. A pond of a square metre, done well, will outperform a large but sterile one every time. What matters is shallow edges, native plants and no fish.

Choosing the spot and settling on a size

Pick somewhere that gets sun for part of the day — ideally four to six hours — and shade for the rest. Full sun overheats the water and encourages blanketweed; deep shade keeps it cold and stops plants flowering. Avoid placing it directly under a large deciduous tree, because a metre of fallen leaves will smother the pond and feed the algae.

Be realistic about what you'll maintain. For a proper wildlife pond, aim for at least 1m by 1.5m, with a deepest point of 60–75cm so frogs can overwinter in the mud at the bottom. Larger is better if you have room: a 2m by 3m pond with a maximum depth of around 90cm holds far more life and stays clearer. If you have toddlers, a raised pond or a sturdy metal grid set just below the surface is a sensible safeguard.

Digging and lining: getting the levels right

Mark the shape out with a hose or a length of rope, then cut the turf and set it aside — it makes a useful edging camouflage later. Dig a shallow shelf around at least part of the perimeter, roughly 20–30cm deep and 30cm wide. This is where marginal plants will sit, and where frogs, birds and hedgehogs come in and out.

From the shelf, dig down to the deepest point in the centre with gently sloping sides rather than sheer walls. Line the hole with soft sand or old carpet as underlay, then use butyl rubber — the most durable option — or a good-quality flexible liner, leaving a generous overlap all round.

Then the most important detail of the whole build: a ramp. A piece of rough timber, a gently sloping gravel beach or a stack of stones in one corner gives wildlife a way out. Frogs and hedgehogs drown surprisingly easily in steep-sided ponds.

Fill it with rainwater from a water butt. If you must use tap water, let it stand for a week before planting anything. Then wait two or three weeks for the water to settle.

Planting: native species that earn their keep

Use native plants, and aim for roughly half the surface to be covered once everything has grown in. That cover gives tadpoles and newts somewhere to hide, and it shades the water enough to keep algae in check.

• Marginals for the shelf: marsh marigold, water mint, brooklime, water forget-me-not, yellow flag iris and ragged robin.
• Submerged oxygenators: hornwort and water starwort, which float freely and soak up nutrients.
• Floating plants: a native water lily in larger ponds, or frogbit and water soldier in small ones.

Plant in baskets of ordinary garden soil, not compost, which is far too rich and leaks nutrients into the water. Top each basket with gravel so the soil stays put.

Avoid invasive non-natives. Floating pennywort, parrot's feather, New Zealand pigmyweed and water hyacinth will wreck a small pond and are illegal to plant in the wild. Never take plants or frogspawn from another pond either — you risk carrying in disease and weed along with them.

Keeping the water clear without chemicals

Green water in the first spring is completely normal, and it usually clears by itself as plants establish. The key is keeping nutrients out: no fertiliser run-off, no fish food, no unnecessary tap water top-ups. Barley straw or a bundle of oxygenators can help in the meantime. Never reach for an algaecide — it will kill far more than the algae.

And please don't add fish. Goldfish and sticklebacks eat frogspawn, tadpoles and almost every insect larva in the pond, and they turn clear water cloudy in weeks. A wildlife pond is a fish-free pond.

Looking after it through the year

Autumn: net out excess leaves, but leave a few in the bottom and keep a bundle of twigs at the edge for newts and insects to shelter in. Resist the urge to tidy the pond — this is when much of its wildlife is settling down.

Winter: float a ball on the surface to keep a hole open in hard frost. Frogs and newts overwinter in the mud and leaf litter, so don't dredge or empty the pond.

Spring: frogspawn usually arrives between February and March. Leave it where it is and don't move it between ponds. Hold off cutting back old growth until late spring, once tadpoles have grown legs.

Summer: top up with rainwater during dry spells and keep the shallow edges clear so birds can bathe. Then simply sit back with a cup of tea and watch. A new pond takes a year or two to find its feet, but once it does, it will quietly become the busiest square metre in your garden.