How to Create a Wildlife Pond in a Small Garden

Why a Small Pond Is Worth the Space

If you only do one thing for wildlife in your garden this year, make it a pond. Water is the single most valuable habitat you can add, and it does not need to be large. A pond just two metres by one, with a deeper middle and a shallow shelf around the edge, will pull in frogs, newts, damselflies and dragonflies within a season or two. Birds will use it constantly for drinking and bathing, and hedgehogs will visit for a drink on warm evenings.

There is a practical bonus, too. A pond is a predator factory. Frogs and toads eat slugs and snails in remarkable numbers, and the insects your pond supports feed the birds that nest nearby. Once it settles, it needs far less attention than a border of bedding plants.

Choosing the Right Spot

Sun is the first consideration. Aim for a position that gets five or six hours of direct light a day, because warmth drives the plant growth and insect activity that make the pond work. A pond in deep shade will sulk, grow little and turn green with algae.

Avoid sitting it directly beneath deciduous trees. Fallen leaves rot down and feed the algae, and tree roots will push at the liner. Keep a couple of metres clear of a mature hedge if you can, but do leave some longer grass, a log pile or a shrub close by. Frogs and newts need damp cover to travel through, and a pond sitting in the middle of bare gravel will be much slower to colonise.

• At least half a day of sun
• Level ground, away from tree roots and heavy leaf fall
• Damp cover nearby — long grass, logs, a shrubby corner
• Somewhere you can actually see it from a window, so you notice what arrives

Digging, Lining and Filling

Mark out the shape with a length of rope or a hose, curving the outline rather than making it a rectangle. Irregular edges give more shallow water, which is where most wildlife happens.

Dig in tiers. Go down to about 60–75cm at the deepest point, which is enough to keep frogs and newts frost-free through winter, and cut a shelf 20–30cm wide at roughly 20–30cm deep for planting. Leave one side as a gentle, gradual slope rather than a cliff, so anything that falls in can walk back out.

Line the hole with butyl rubber, at least one millimetre thick — it is far more durable than the thin polythene sold for the job. Bed it on an underlay of geotextile fleece or old carpet to protect it from stones. Allow about 30cm of liner overhang all round, and tuck this under turf or hide it beneath paving and gravel later. Fill with rainwater from a water butt rather than the tap; mains water is rich in nutrients and will trigger an algae bloom. If you must use tap water, let it stand for a few days first and expect a green phase.

Native Plants That Do the Heavy Lifting

Aim to cover between a third and a half of the surface with plants. They shade the water, starve algae of light and give amphibians somewhere to hide and spawn.

• Oxygenators: hornwort and water starwort, which live below the surface and keep the water clear
• Marginals for the shelf: marsh marigold, water forget-me-not, brooklime, water mint and lesser spearwort
• Floating cover: a small native water lily or frogbit, which shades the surface
• Edges: ragged robin, sedges and, in a slightly bigger plot, purple loosestrife

Please avoid the invasive non-natives — floating pennywort, parrot's feather and New Zealand pigmyweed. They are illegal to plant in the wild and will smother a small pond in a single season. Plant in baskets of hessian or a low-nutrient aquatic compost, and never use ordinary garden soil, which is far too rich.

Keeping Wildlife Safe

The biggest killer of garden pond wildlife is not cold or predators, it is steep sides. Frogs, hedgehogs and even birds can drown in a pond they cannot climb out of.

• Build a shallow beach of pebbles or gravel along one edge
• Stack a few stones or lay a rough log so it slopes into the water
• Leave trailing plants over one side as a ladder for small creatures
• Do not add fish — they eat tadpoles and almost everything else

Never use chemicals near a wildlife pond, including slug pellets and weedkiller. If you have toddlers, either raise the pond above ground with a sturdy ledge or fit a rigid mesh cover that wildlife can pass through.

Looking After It Through the Year

Spring is the payoff. Frogspawn usually appears between late February and March, and you should leave it exactly where it is. By May the pond will be alive with tadpoles, diving beetles and the first damselflies emerging from their nymph cases on the stems.

In summer, top up with rainwater during dry spells and thin duckweed with a rake if it blankets the surface — leave the rakings on the side for a day so anything caught can crawl back. In autumn, resist the urge to cut everything back. Hollow stems and seed heads are winter homes for insects, so leave them standing until March. Net out fallen leaves before they sink and rot.

In freezing weather, do not smash the ice with a hammer; the shock harms everything beneath. Float a ball to keep a small gap open instead. Then do as little as possible, and let it get on with the job.