Why a Pond Is the Best Wildlife Investment on Your Plot

If you do only one thing for wildlife on your smallholding this year, make it a pond. Nothing else you can create delivers so much for so little. Within a season of filling with water, a well-sited pond will draw in frogs, newts, dragonflies, damselflies and a startling array of beetles and bugs. Birds will visit to drink and bathe, hedgehogs will stop by for a sup, and bats will hunt the insects rising off the surface at dusk.

The good news is that a wildlife pond is far less work than a formal one. No filters, no pumps, no regular feeding and no need to keep it crystal clear. In fact, murky green water in a new pond is a sign of life, not failure. Your job is simply to dig the right hole in the right place and then, for the most part, stand back.

Choosing the Right Spot

Position is everything, and the single most common mistake is putting a pond too close to trees. Leaves are the obvious problem — a pond under a sycamore will fill with leaf litter each autumn, and that rotting vegetation strips oxygen from the water and smothers the bottom. But roots are the deeper issue. Willows and poplars in particular send out aggressive roots that can puncture a liner, and even a modest oak or ash will draw heavily on the water table around it.

Aim for at least ten metres from the nearest large tree, and further if you can manage it. Beyond that, look for:

• Plenty of sun. A pond that gets six hours or more of direct light a day will warm up faster and support far more life. Some afternoon shade is fine and helps prevent the water getting too hot in a July heatwave.
• A natural low point. If there is a damp dip in a field or a corner where water already gathers after rain, that is your spot. You will spend less time topping it up.
• Shelter from prevailing wind, ideally from a hedge or a bank, so the surface stays calm and emerging insects are not blown away.
• Easy access for you. You will want to watch it, and occasionally clear it, so avoid tucking it into an inaccessible corner.

Keep it away from any area where you spread slurry, use weedkiller or store fuel, and never site a pond where run-off from a yard or track can reach it.

Digging and Lining: The Practical Bits

Aim for a pond roughly 2–3 metres across and 60–80 cm deep at the centre. That depth keeps the water cool in summer and stops it freezing solid in winter, which matters enormously for frogs and newts overwintering in the mud. Shallower ponds dry out in a dry spring and lose their spawn before it hatches.

Profile the hole with gently sloping sides, not vertical walls. Create at least one shallow shelf around the edge, roughly 20–30 cm deep, where marginals can be planted and where birds and hedgehogs can safely enter and exit. A rough ramp of stones or a piece of log laid into one corner gives creatures a way out if they fall in.

For lining, butyl rubber is the reliable choice, though heavy-duty flexible liner of any kind works well. Line the hole with a layer of old carpet, sand or soft earth first to protect the rubber from stones. Leave a good overhang around the edge, then bury it under turf or soil so no liner is visible. Rainwater will fill the pond, though you may want to top it up initially with water from a water butt rather than a hose, which can carry chlorine and nutrients.

Planting the Native Way

Native plants are not just a nice touch — they are the engine of the whole system. Our insects have evolved alongside them, and many will not lay eggs on anything else. Avoid the colourful exotic varieties sold in garden centres and steer clear of anything invasive.

Good choices include:

• Oxygenators: hornwort, water starwort and spiked water-milfoil, planted in the deepest section.
• Marginals: marsh marigold, water forget-me-not, purple loosestrife, soft rush and ragged robin along the shallow shelf.
• Floating: a small clump of native water lily in a larger pond, though be prepared to thin it.

Plant in late spring once the water has warmed. Use baskets of hessian or open-mesh to make future thinning easier, and top them with gravel to stop soil clouding the water. Resist the urge to overplant — a third of the surface covered in vegetation is plenty. Some open water is essential for dragonflies and for birds to drink.

Let It Colonise Naturally

This is the part that tests the patience of anyone who likes a tidy plot. Do not introduce frogs, newts or fish. Frogs and newts will find a new pond remarkably quickly on their own, often within a single season, travelling overland from neighbouring ditches and wet corners. Fish, on the other hand, will eat almost everything else, so leave them out entirely in a wildlife pond.

Neither should you worry about buying in pond snails, water beetles or dragonfly larvae. Given a clean, chemical-free pond with native plants nearby, natural colonisation does the work. The first arrivals are usually water boatmen, diving beetles and midges, followed by damselflies and, if you are lucky, dragonflies. Algae will bloom in the first year and then settle as plants establish and shade the water.

Keep the surrounding habitat rough and varied — a patch of long grass, a log pile, some nettles and a hedge nearby — so that amphibians have somewhere damp to shelter outside the breeding season. One last thing: never use tap water to top up a pond containing frogspawn, and never introduce goldfish or duckweed. Both will undo your good work faster than you can say "blanket weed". Give it two or three years, and your pond will be the busiest square metre on the whole holding.