A Pond Is the Best Single Addition You Can Make

Of all the improvements you can make for wildlife on a smallholding or in a country garden, a shallow pond gives the greatest return for the least effort. Frogs, toads, smooth and palmate newts, dragonflies, damselflies, diving beetles and pond skaters will all arrive without any help from you. Above the water, swallows and house martins will hunt, bats will drink on the wing at dusk, and blackbirds and song thrushes will use the shallow margins as a bath.

You do not need a large pond. A well-planted pond of two metres by three is a genuine wildlife asset, and a buried half-barrel or old butler sink will still pull in insects and amphibians. What matters is the design: shallow, gently sloping edges, native planting, and a resolution to leave it largely alone.

Choosing the Spot: Sunlight, Runoff and Shelter

Position does more for a pond's long-term health than any other decision. Aim for at least six hours of direct sun a day if you can. Dragonflies need warmth to hunt and lay, and flowering marginals such as water mint and purple loosestrife will sulk in deep shade. A little afternoon shade helps keep algae in check, so partial shade is not a problem.

There are a few places to avoid:

• Under mature trees. Leaf fall clogs the water and roots can puncture a liner.
• The very lowest point of the garden if that is where runoff collects from roads, yards or fields. Nutrient-rich water fuels blanketweed, and any pesticide or fertiliser residue that reaches it can wipe out amphibians.
• Directly below a sprayed crop or a busy yard. Keep a buffer strip of rough grass between the pond and any treated ground.

Put it somewhere you will see it daily — near a kitchen window or along a path — and you will notice far more. If your site is a Site of Special Scientific Interest, on a floodplain, or you are planning something much larger than a garden pond, have a word with your local authority first. For a normal garden pond, no permission is usually needed.

Getting the Shape and Depth Right

Wildlife ponds should be shallow and generous at the edges. Dig an irregular outline rather than a neat oval, then work in three zones:

• A shallow shelf of 5–10cm depth for birds to bathe and for dipping.
• A marginal shelf at 20–30cm, about 30cm wide, for flowering plants.
• A central area 60–80cm deep, which stays unfrozen at the bottom in all but the hardest winters and gives newts and frogs somewhere to overwinter.

Make at least one edge a gentle slope, no steeper than about one in four, so that hedgehogs, frogs and fledglings can walk out. A vertical liner edge is a death trap for small mammals. A rough, undulating profile with a few stones and a log half-submerged at the margin will be used by everything from dragonfly larvae to drinking bees.

Lining and Filling Without Fuss

Once dug, remove sharp stones and any cut roots, then line the hole with sand and a layer of old carpet or purpose-made underlay. A butyl liner of at least 0.75mm, ideally 1mm, will last decades. Leave 30–40cm of liner beyond the edge and fold it into a shallow trench, then hide it under turf, stones or gravel so it looks settled within a season. Preformed rigid liners are easier but rarely deep enough.

Fill with rainwater from a butt if you have it, or mains water — the chlorine dissipates quickly and does no lasting harm. Let the pond stand for a week or two before planting so the water settles and warms. Most importantly: do not add fish. Goldfish and even small native fish will clear out tadpoles, larvae and invertebrates, and the pond becomes a tank rather than a habitat.

Never take water, plants or spawn from a wild pond. Invasive species and amphibian disease travel that way with depressing ease. Everything you want will find your pond on its own.

Native Plants That Do the Work

Plant in baskets of loam, or straight into a soil-lined base if you have one, and keep fertiliser well away. Aim to cover between a third and a half of the surface, no more.

• Oxygenators: hornwort, common water starwort and curled pondweed.
• Marginals: water forget-me-not, water mint, marsh marigold, lesser spearwort, purple loosestrife and flowering rush. Keep yellow flag iris in a basket — it is vigorous.
• Floating: a dwarf water lily for small ponds; native white water lily only if you have real space.

Steer clear of New Zealand pygmyweed, floating pennywort, water fern and parrot's feather. They are banned from sale here and can smother a pond in a season. Never tip pond plants or water into a ditch or watercourse.

Letting Wildlife Find It, and Keeping It Healthy

Water beetles, pond skaters, daphnia and damselflies typically appear within weeks. Frogs often arrive within a season; newts take longer. Let them come.

Maintenance is mostly restraint. Net out fallen leaves in autumn but leave a few. Pull excess blanketweed by hand in spring rather than reaching for a chemical. Keep the surrounding margins long and rough, and leave a log pile or leaf mound nearby for hibernation. Top up in dry spells with rainwater from a butt kept beside the pond, and never empty or drain it in winter.

If you are lucky enough to find great crested newts, remember they are a protected species — leave them undisturbed and take advice. And keep slug pellets, insecticides and herbicides well away from the pond and everything that drains into it. A quiet, well-edged, native-planted pond will look as though it has always been there, and within two or three years it will be the busiest corner of the place.