Creating a Wildlife Pond in a Small Garden

Why a Small Pond Is Worth the Digging

Water is the single most valuable thing you can add to a British garden. Even a pond no bigger than a dining table will draw in creatures from gardens and hedgerows around you, and it will do it without pumps, filters or any expensive kit. Frogs, smooth newts, damselflies and a whole cast of insects need water at some point in their lives, and in a country where we have lost so many field ponds, a small garden pool is a genuine refuge.

The best news is that a wildlife pond is not a goldfish pond. You are not aiming for clear water and tidy edges. You are aiming for a bit of a jungle, and that is far easier to look after.

Choosing the Spot and Working Out the Size

Pick somewhere that gets sun for at least half the day. Warmth brings out dragonflies and helps the plants grow, though a little shade in the afternoon is no bad thing in a hot summer. Keep it away from the drips of a large tree, partly because of falling leaves and partly because roots can puncture a liner when you dig.

Depth matters more than width. A pond of around 1.5 metres by 1 metre, with a deepest point of 45 to 60 centimetres, will stay cool in summer and rarely freeze solid in winter. If space is tight, a half barrel or a buried washing-up bowl will still work. Aim for the biggest you can comfortably manage — two square metres is a lovely garden pond.

Getting the Shape and Depth Right

Amphibians and insects need shallow water and easy exits, so build in gentle slopes rather than cliff faces.

• Dig a shallow shelf about 20 to 25 centimetres deep around one or two sides for marginal plants and for frogs to sit on.
• Make one end a gradual ramp — a sloping "beach" of stones, gravel or rough timber — so hedgehogs, birds and small mammals can drink and climb out if they fall in.
• Keep the deepest section in the middle, and try to make the sides as vertical as you can below the shelf to stop soil washing in.
• Line with butyl rubber about 1 millimetre thick, laid over old carpet, sand or underlay to protect it. Leave a 20 to 30 centimetre overlap and tuck it into a shallow trench around the edge, then cover the rim with turf, stones or gravel.

Fill with rainwater from a water butt if you can. Tap water will not poison anything, but it carries nutrients that feed algae, so you may get a green flush for the first few weeks either way. Do not worry — it settles.

Planting with Native Species

Aim for roughly half the water surface covered in plants, and keep them native. Plant into baskets of heavy garden soil or subsoil topped with gravel, or straight into a layer of soil on the shelf. Do not use rich compost, as it leaks nutrients into the water.

• Oxygenators: hornwort and water starwort, which float freely and shelter tadpoles and insects.
• Marginals for a small pond: marsh marigold, water forget-me-not, water mint, brooklime and lesser spearwort. These are well behaved and flower generously.
• Floating plants: a little frogbit for shade and cover. Keep it in check.
• Avoid invasive species. New Zealand pygmyweed, water fern and parrot's feather are serious problems and should never be planted. Yellow flag iris and purple loosestrife grow too large for a tiny pond.

Leave a damp, planted margin around the edge with ragged robin, bugle or soft rush. That boggy strip is where a lot of the life actually happens.

The Wildlife That Turns Up

Common frogs usually arrive first, often within a season, followed by smooth and palmate newts. Damselflies such as the large red and dragonflies like the common darter will patrol the surface, and they breed in surprisingly small ponds. Look for pond skaters, water boatmen, lesser water boatmen, diving beetles and caddisflies among the stems. Birds come to drink and bathe, and bats will hunt insects over the water at dusk.

One thing to resist is fish. Goldfish and even sticklebacks will hoover up tadpoles, newt larvae and most of the invertebrates, and the pond will feel empty for it.

Looking After It the Lazy Way

Wildlife ponds thrive on a bit of neglect. Do not tidy up in autumn — leave seed heads, hollow stems and leaf litter as shelter for overwintering insects and amphibians. If leaves blow in, skim some out but leave a few; they are part of the system.

• Top up with rainwater in dry spells rather than tap water where possible.
• In midsummer, twirl excess blanketweed or duckweed around a stick and leave it on the edge for a day so anything caught up can crawl back.
• Never use pesticides, slug pellets or fertiliser anywhere near the pond or its margin.
• Leave a log pile, a stone heap and a patch of long grass nearby so frogs and newts have somewhere to shelter and hibernate.

Give it a year before you judge it. A pond settles into its own rhythm, and the creatures that find it will do most of the work for you.