Why Even a Tiny Pond Matters

Of all the things you can do for wildlife in a small garden, a pond is almost certainly the most valuable. Water is scarce in the modern landscape — so many ponds have been filled in, drainage ditches piped away and garden lawns stripped of their damp corners — that a single square metre of clean, plant-filled water can become a local hub. Frogs and toads will find it within a season or two, often crossing several gardens to get there. Damselflies and dragonflies will patrol it. Birds will drop in to drink and bathe, bats will hunt insects above the surface at dusk, and hedgehogs will come for a quiet drink on a summer evening.

A pond does not need to be grand. A sunken washing-up bowl, a half-barrel, an old butler sink or a piece of liner dug into a border can all work. What matters is the shape of the edges, the plants you choose and the way you look after it.

Choosing the Spot

Aim for somewhere with four to six hours of direct sun a day. Too much shade and the water stays cold and plants sulk; full sun all day and you will be endlessly scooping out blanket weed. A little dappled shade in the afternoon is ideal.

• Avoid ground beneath large trees — fallen leaves rot and feed algae, and roots can puncture a liner.
• Keep it away from the house if you have toddlers, or raise it on a sturdy plinth with a pebble beach set back from the edge.
• Site it where you can see it from a window; you will notice far more.
• Choose level ground if you can — a sloped site means the water will try to find its own level and may expose the liner.

A pond of roughly one metre by one and a half metres is plenty. Dig the centre to about 45cm so frogs and newts can overwinter below the frost line, and keep at least one side shallow.

Digging, Lining and Filling

Mark out a soft, kidney-shaped curve with a length of rope or an old hosepipe — straight edges look artificial and give wildlife fewer places to hide. Then work in layers:

• Dig a shelf 10–15cm deep around part of the perimeter for marginal plants.
• Take the centre down to 45cm, with a gentle slope rather than a cliff between the two.
• Shape one side into a shallow ramp — a beach of pebbles and soil that creatures can walk in and out of.
• Line the hole with a 2–3cm layer of soft sand, or reuse old carpet and underlay, to protect the liner from stones and roots.
• Lay butyl or EPDM liner with plenty of overlap, tuck it into the shelves and weigh the edges down with turf or stones.

Fill with rainwater from a butt or buckets if you possibly can. Tap water is rich in nutrients and chlorine, which encourages algae, so if you must use it, let the pond stand for a fortnight before planting. Leave the water to settle and warm for a week or two.

Planting With Native Species

Native plants support far more insect life than exotic ones, and they look right. In a small pond, restraint is everything: three to five marginals, a couple of oxygenators and perhaps one small floating plant is ample. Overplant and you will spend every summer thinning.

• Marginals: water forget-me-not, marsh marigold, brooklime, water mint, lesser spearwort, creeping jenny and ragged robin all suit small ponds.
• Oxygenators: hornwort, water starwort and curled pondweed keep the water clear and give tadpoles cover.
• Floating: a pygmy water lily or a little frogbit provides shade without smothering the surface.

Plant in baskets of plain loam — no fertiliser, which would trigger an algae bloom — and set them on the shelves so the rim sits just below the water. Never take plants from the wild, and avoid invasive thugs such as New Zealand pygmyweed, parrot's feather and floating pennywort.

Making It Safe for Wildlife

The single most important feature is an easy way out. Frogs, hedgehogs and even birds can drown in a pond with sheer sides.

• Leave at least one long, gentle slope or pebble beach.
• Sink a piece of weathered log or a short plank at an angle as an escape ramp.
• Add a few stones and a small log pile nearby as shelter for amphibians and insects.
• Do not introduce fish — they eat tadpoles and insect larvae and turn clear water cloudy.
• Skip pumps and fountains; still water is what wildlife wants, though a solar bubbler in hot spells is harmless.
• Let the surrounding grass grow a little longer and leave seed heads standing into winter.

If you suspect great crested newts have moved in, leave them well alone — they are legally protected, and advice should be sought before any work.

Caring for It Through the Year

Autumn is the moment to stretch a net over the pond for a few weeks and clear fallen leaves, which would otherwise rot and feed the algae. In spring, cut back dead stems and thin vigorous plants, but leave any trimmings on the edge overnight so that creatures can crawl back into the water. Scoop out excess blanket weed with a stick twirled through it, and top up with rainwater in dry spells.

Never empty and scrub a pond — that destroys the whole community in one afternoon. With a little patience, this small patch of water will quietly become the busiest corner of your garden.