Why even a tiny pond earns its place

Water is the single most valuable thing you can add to a garden. A pond the size of a dining table will draw in wildlife from a surprisingly wide area, because standing water is genuinely scarce across much of Britain. Frogs and smooth newts will find it within a season or two, often crossing several gardens to get there. Damselflies and dragonflies arrive from above, and thirsty birds — blackbirds, blue tits, sparrows, even the occasional song thrush — treat a shallow edge as both bath and drinking fountain. Put a few stones and a small log pile alongside it and you have a working little ecosystem in a corner that might otherwise hold nothing but a sulking shrub.

You do not need acreage. A pond of roughly 1.2 metres by 1.8 metres, properly built, will support far more life than a much larger one with steep sides and no planting.

Choosing the right spot

Pick somewhere that gets sun for part of the day but is not baked from dawn to dusk. Full sun encourages algae and warms the water too quickly; deep shade keeps it cold and stops plants flowering. Dappled light with a few hours of direct sun is ideal.

Keep it away from large trees. Fallen leaves rot down and feed the water, and thirsty roots will happily push through a liner in search of moisture. A spot you can see from a kitchen or living room window is worth more than you might think — you will notice far more of what visits.

• Level ground, so the water sits evenly and you are not fighting a slope.
• Reachable with a hose or watering can for topping up in dry spells.
• Clear of the vegetable patch, so you are not spraying anything nearby.

Digging the hole: shape matters more than size

The profile of your pond decides how much wildlife it can hold. Aim for three zones: a shallow beach, a mid-depth shelf and a deeper centre.

• The beach: a gentle slope at one end, running from dry ground into about 5 centimetres of water. This is the single most important feature. Frogs, newts, hedgehogs and fledgling birds all need a way in and out. A steep-sided pond is a trap.
• The shelf: about 20 to 25 centimetres deep, wide enough for marginal plants and for a blackbird to stand and bathe.
• The centre: 60 to 75 centimetres, so frogs and newts can overwinter in the mud below the ice and the water stays cooler in summer.

Line the hole with soft sand or old carpet, then underlay, then butyl or EPDM rubber. If that sounds daunting, a rigid preformed liner is a perfectly respectable shortcut — just check it has a built-in shallow shelf. Leave a generous overlap all round and tuck the edges under turf or flat stones, which also gives insects somewhere to bask.

Fill it with rain, not tap water

Tap water carries chlorine and, more importantly, nutrients that fuel algae. If you can, let the pond fill from rain alone, or top it up from a water butt. If you must use tap water, let it stand in a can for a day or two first and expect a green flush for a few weeks.

Then leave it alone. A new pond looks like cloudy nothing for a fortnight while the microscopic life establishes itself. This is normal, and it is the foundation of everything that follows. Do not add fish — even a couple of goldfish will strip a small pond of tadpoles, insects and larvae within a season.

Plant it with British natives

Native plants support far more insects than garden centre exotics, and they will not escape and smother a wetland. Aim to cover roughly a third of the surface with plants, leaving open water for birds to land on.

• Oxygenators: hornwort and water starwort, which live below the surface and keep the water clear.
• Marginals: marsh marigold, water forget-me-not, water mint, lesser spearwort and yellow flag iris.
• Floating: a small native water lily, if you have the room and the depth.

Please never take plants or frogspawn from the wild, and do not move them between ponds. Diseases such as ranavirus and chytrid fungus spread that way, and a pond in the next county is not the same habitat as yours. Avoid the thugs, too: floating pennywort, New Zealand pygmyweed, water fern and parrot's feather are all invasive and illegal to allow into the wild. Great crested newts are fully protected by law, so if you are lucky enough to find them, enjoy them and leave them undisturbed.

Looking after it, lightly

Once established, a wildlife pond needs less work than a lawn. Twist blanketweed out with a stick in spring rather than reaching for chemicals. Sweep fallen leaves off the surface in autumn before they sink. Top up with rainwater during dry spells. Keep a third of the surface clear of vegetation so birds can land, and leave the surrounding long grass and log piles alone — that messy fringe is where frogs spend most of their lives.

Above all, resist the urge to tidy. A pond that looks a little wild is a pond that is working.