Harriet Cooper
Why a Small Pond Is the Best Thing You Can Add to a Garden
If you do only one thing for wildlife this year, make it a pond. Even a modest one — a single square metre of water sunk into a corner of the garden — pulls in creatures you simply will not see otherwise. Frogs and common newts arrive within weeks, often from nowhere it seems, drawn by the moisture and scent of a new habitat. Dragonflies and damselflies follow in summer, laying eggs among the stems, while birds queue up to bathe and hedgehogs drop by for a drink on warm evenings.
A pond is also the feature that works hardest during a drought. When everywhere else dries out, a well-sited pool remains a lifeline. You do not need a large plot, a pump, or expensive kit — just a hole, a liner, rainwater and a little patience.
Pick a Spot with Sun and Shelter
Choose somewhere that gets sun for at least half the day. Warm water means more insect life, which means more food for everything else. A little afternoon shade is fine and helps keep algae in check, but a pond in deep shade will be sluggish and disappointing.
- Keep it away from large trees, whose leaves will fill the water every autumn and whose roots may puncture the liner.
- Avoid the lowest corner of the garden if it collects runoff, which can carry nutrients and garden chemicals in with it.
- Site it where you can see it from a window. You will watch it far more often than you expect.
- Leave rough grass, a log pile or a shrubby edge nearby so amphibians have somewhere damp and safe to hide.
Digging and Lining Your Pond
Aim for roughly 1.5 metres by 1 metre if you have the room, with a centre depth of around 45 to 60 centimetres. That depth keeps the water cool in summer and stops it freezing solid in winter, which matters enormously for frogs and newts overwintering at the bottom.
Build in a shallow shelf about 20 to 25 centimetres deep along at least one side for marginal plants, and slope one end gently like a beach. That ramp is the single most important feature for wildlife — without it, hedgehogs, frogs and even birds can climb in and drown.
Mark out the shape with string or sand, then lift the turf and set it aside. Dig the hole, removing sharp stones and roots. Line it with soft sand or old carpet, then a purpose-made underlay, and finally butyl or EPDM liner. Leave a generous 15 to 20 centimetres of liner overlapping the edges all the way round, ready to tuck under turf or stones later.
Fill it with rainwater from a water butt if you can. Tap water contains chlorine and phosphates that feed algae; if you must use it, let it stand for a few days first. Then walk away and let the pond settle for a week or two before planting.
Planting for Wildlife, Not Just Looks
Native plants do far more for wildlife than showy exotics. Aim to cover about a third of the water surface, no more, or the pond will become a solid mat of greenery.
- Oxygenators: hornwort and water starwort, weighted and dropped in or grown in baskets.
- Marginals: marsh marigold, water forget-me-not, lesser spearwort and water mint along the shelf — keep the mint in a basket, as it spreads.
- Floating: a small native water lily such as the pygmy white water lily.
Use baskets filled with loam or ordinary garden soil rather than rich compost, and top them with gravel so the soil does not wash out. Avoid invasive non-natives entirely — parrot's feather and New Zealand pygmyweed will smother a small pond within a season.
Small Touches That Make a Big Difference
- Do not add fish. Goldfish and even sticklebacks eat tadpoles and larvae, and a small wildlife pond cannot support them.
- Skip the pump and fountain. Still water is what amphibians and dragonfly larvae want.
- Stack a few stones or a log at the edge, half in and half out of the water, as perches for emerging dragonflies.
- Leave a patch of longer grass and a small log pile within a metre or two of the pond.
- Never use slug pellets or other chemicals nearby. Amphibians absorb water through their skin and are very vulnerable.
Looking After Your Pond Through the Year
Spring is for watching. Frogspawn appears in February or March, newts return to the water, and the first damselflies emerge. Twirl blanketweed out with a stick rather than treating it — it is a nuisance, but it is also habitat, so leave some behind.
Through summer, top up with rainwater during dry spells. A pond that dries out occasionally is not a disaster, but a permanent pond should not shrink too far, so keep a water butt handy.
In autumn, net out excess fallen leaves before they rot, but leave a few in the water for invertebrates. Do not cut back all the marginal growth; hollow stems are where many insects overwinter.
In winter, never smash the ice — the shock waves can harm amphibians resting below. Rest a pan of hot water on the surface to melt a hole instead, and leave it there for a few minutes. That single hole lets gases escape and keeps the pond healthy until spring.
