The best thing you can do for wildlife

If you do only one thing for nature in your garden this year, make it a pond. Even a modest one — a repurposed butler sink, an old Belfast sink, or a lined hollow a couple of metres across — will pull in more species than a border full of flowers ever will. Within a season you can expect frogs, water beetles, pond skaters and the first damselflies; within a few years, newts, dragonfly nymphs and a whole invertebrate community that feeds the birds and hedgehogs that visit after dark.

The reason is simple: water is scarce in the landscape. Most gardens are dry, tidy and enclosed, and a pond offers drinking water, breeding water and a damp, shady refuge all in one. You do not need a pump, a filter or a single goldfish. In fact, the less machinery and the fewer fish, the more wildlife you will get.

Choosing the right spot

Position matters more than size. Aim for a spot that gets sun for at least half the day — amphibians spawn in the warm shallows and dragonflies need warmth to fly — but tuck one edge into shade or beside long grass so creatures have somewhere to retreat. A quiet corner, away from the patio and the back door, will always outperform a pond in the middle of a busy lawn.

• Avoid overhanging trees. Fallen leaves rot down and turn the water sour, and roots can puncture a liner.
• Keep it away from low-lying ground where runoff from sheds, drives or fields collects — you risk pollution and nutrient-rich water.
• Choose level ground so the water sits evenly at the rim, and site the pond where you can reach it with a watering can from a rainwater butt.
• Check for buried services — cables, pipes and drains — before you dig.

Think about how you will see it, too. A pond you can watch from a kitchen window or a bench will be looked after far better than one hidden behind the shed.

Getting the shape and depth right

Wildlife-friendly ponds are shallow-edged and irregular. Rather than a steep-sided tub, dig a profile with a beach of gravel sloping in at one end, a broad shelf just below the waterline, and a deeper section in the middle. A typical small garden pond might be 1.5–2 metres across, with a shelf 20–30cm deep for marginal plants and a centre around 60cm deep so frogs and newts can overwinter in the mud without freezing solid.

Line with a butyl or flexible liner, cushioned with old carpet or sand, and leave the edges uneven — an overlap covered with turf, stones or gravel looks natural within weeks and gives amphibians a way in and out. Fill from a rainwater butt if you can; if you must use tap water, let it stand for a few days before planting, as the chlorine disperses.

Planting a native pond

Plants do the heavy lifting: they oxygenate the water, shade out algae and provide egg-laying sites, perches and cover. Use a mix of marginals, oxygenators and a little floating cover, and — crucially — avoid invasive non-natives such as floating pennywort, New Zealand pygmyweed and water hyacinth, which can smother a pond and spread into the wild.

• Marginals: marsh marigold, water forget-me-not, water mint, ragged robin, lesser spearwort and purple loosestrife. Yellow flag iris is lovely but vigorous — keep it in a basket.
• Oxygenators: hornwort and water starwort, planted in baskets of loam or weighted bunches.
• Floating cover: a single water lily or frogbit for shade, but leave at least a third of the surface open.

Plant in aquatic baskets with a low-nutrient loam rather than compost, which leaks nutrients and fuels blanketweed. Then step back and leave the water to clear on its own — it will look green for a few weeks, then settle.

Making it safe for everything that visits

A pond with sheer sides is a trap. Hedgehogs can swim well but cannot climb out of a steep liner, and so drown. Always provide a gently sloping ramp — a plank wrapped in sacking, a pile of stones, or a gravel beach — at one or two points, and keep the water level within a few centimetres of the rim so small mammals can climb out.

Resist the urge to add fish. Even a few will clear the tadpoles, newt larvae and invertebrates that make a pond worth having. Avoid insecticides, slug pellets and weedkillers anywhere near the water, and never tip in garden chemicals or excess pond weed. If you have small children, either fence the pond or make the edges shallow and supervise closely — a pond with a broad shelf and a covering of sturdy mesh just below the surface is a common compromise.

Looking after it through the year

Ponds reward neglect. Top up in dry spells with rainwater, and in autumn net out or rake off fallen leaves before they sink, leaving them on the bank for a day so any creatures can crawl back. In late summer, thin oxygenators and marginals by hand, leaving the cuttings on the side overnight. Each spring, clear a little duckweed and watch for frogspawn in the shallows — the surest sign that your quiet corner has become part of the countryside again.