Small Structures, Big Benefits

A pond is only half a habitat. The creatures that make it worthwhile — common frogs, smooth newts, diving beetles, dragonfly nymphs, the occasional toad — spend far more of their lives in the damp tangle of the margins than in open water. A tidy pond with a close-mown edge and a bare shelf of stone is a poor home, however clear the water looks. Logs, stones and a decent layer of leaf litter give them humidity, cover and somewhere to hide from frost, drought, cats, herons and each other.

The good news is that this is some of the cheapest and most rewarding water gardening you can do. It takes an afternoon, it costs very little, and it improves steadily as the wood rots and the moss moves in.

Choosing and Siting Logs

Use untreated timber and nothing else. Tanalised, creosoted or varnished wood will leach things you would rather not have in a wildlife pond. Oak, ash, beech, apple and hawthorn are excellent choices; dense hardwoods rot slowly and last for years, feeding beetles, woodlice and fungi as they go. Hollow logs are the most valuable of all, so if a tree comes down nearby, beg a section of it.

• If you have only solid timber, drill a scattering of 8–10mm holes along one face for solitary bees and small beetles.
• Lay one log lengthways with one end in the water. This is the classic newt ramp and emerging dragonfly platform, and it is the single most useful thing you can add.
• Stack the rest at right angles in a loose criss-cross heap, leaving the middle open rather than tight.
• Push soil and leaf mould into the gaps, then partly bury the bottom layer for steady humidity.
• Keep the heap mostly above the winter waterline so hibernating animals do not drown.

Stones and Rock Piles

Aim for an open jumble, not a wall. Cemented or close-fitting stonework has no cavities, and cavities are the whole point. Where the bank meets the water, build an informal shelf of stones so the water laps in and out between them; this is where froglets and newt efts will spend their first weeks ashore.

• Mix sizes: palm-sized stones for ground beetles and spiders, larger blocks for frogs and toads to squeeze beneath.
• Some stones should face the sun for basking; leave others in shade where damp, cool conditions suit slugs, newts and amphibians.
• If you are placing stones near a butyl or EPDM liner, put a protective underlay or fleece beneath them. Sharp edges and heavy weights are the usual cause of a leak.
• Limestone and chalk slowly raise pH. That is fine for most ponds, but choose slate or granite if you are looking after acid-loving bog plants.

Leaf Litter and the Soft Furnishings

Leaves are habitat, not mess. Oak, beech and hornbeam break down slowly and make excellent cover and food for tadpoles, caddis larvae and freshwater shrimp. A heap of them tucked into a corner of the margin will be full of life within weeks.

Do be sensible about quantity. In a small pond, a thick blanket of leaves will rot, consume oxygen and turn the water black. A couple of handfuls scattered in the shallows is plenty; take the rest to the compost heap. Resist the leaf blower along the pond edge — rake gently and leave the debris where it falls, since the damper corners are where frogs and newts choose to sit out dry spells.

Leaving Gaps and Corridors

Wildlife gardening is mostly about gaps. Invertebrates need openings of roughly 2–3cm to move between cavities, and amphibians want something more like 10–15cm. If you seal your stonework with soil, or butt logs tightly together, you have built a monument rather than a refuge.

• Leave deliberate gaps at the base of the heap, facing different directions.
• Connect your piles to other habitat — the base of a hedge, rough grass, a dead hedge — so animals can travel without crossing open ground.
• Always provide an easy exit from the pond. Amphibians drown in steep-sided water with no ramp, and hedgehogs benefit from a gently sloping stone or plank at the edge too.
• Avoid netting over or around the shelves, which traps wildlife.

Looking After It Through the Year

Once built, the best thing you can do is mostly nothing. In spring, check for frog and newt spawn and then keep well away; the piles are nursery, larder and shelter at once. Through summer, top up water from a butt rather than the tap, and keep the logs damp by splashing them occasionally. In autumn, add a few more leaves and resist the urge to tidy. In winter, do not move logs or stones at all — frogs, newts and many insects hibernate underneath, and a single frosty afternoon of rearranging can undo a whole year's work.

Do add fresh timber each year to replace what has rotted away. The rot itself is the point: decaying wood feeds an entire chain of insects and fungi, which in turn feeds the birds and amphibians that make a pond feel alive. Build it loosely, leave the gaps, and the creatures will find it on their own.