Encouraging Frogs and Hedgehogs for Natural Pest Control

Why Your Best Pest Control Team Is Already Out There

Every allotment and back garden in the country is crawling with slugs, snails and caterpillars, and every one of them has natural predators looking for a meal. The trick isn't to wage war with pellets and sprays, but to make your plot irresistible to the creatures that do the job for free. A frog will happily eat its own body weight in slugs and beetles each week. A hedgehog can cover two kilometres in a single night, hoovering up slugs, snails, beetles and leatherjackets as it goes. Give them somewhere to shelter, drink and hibernate, and they will repay you handsomely.

Better still, this is a job you do once. A pond, a log pile and a scruffy corner take an afternoon to create, then quietly get on with supporting wildlife year after year while you focus on your runner beans.

Building a Pond, However Small

Frogs and toads need water to breed, and even a washing-up bowl sunk into the ground will do. If you have room, aim for something around a square metre, with a shallow shelf at one end and a deeper section of 45–60cm at the other. The shallow shelf warms up quickly in spring and is where frogs will spawn; the deeper part gives them somewhere to retreat from frost and herons.

• Site it in part shade. Full sun encourages algae; deep shade leaves the water too cold for tadpoles.
• Add a gentle ramp. A plank of wood or a sloping pile of stones lets hedgehogs and fledgling birds climb out if they fall in. An escape route is essential.
• Plant native oxygenators. Hornwort and water starwort keep the water clear, while marsh marigold and ragged robin around the edge give amphibians cover.
• Skip the fish. Goldfish eat tadpoles, and the whole point is to raise a frog army, not a pet.
• Fill with rainwater. Tap water contains nutrients that feed algae. A water butt is ideal.

Newts, dragonflies and damselflies will find a pond within a season or two, and they bring their own pest-munching habits with them.

Log Piles, Stone Walls and Compost Heaps

Amphibians spend most of their lives out of water, hiding in cool, damp places during the day and hunting at night. A log pile in a shaded corner is perfect: stack old branches, offcuts and prunings loosely rather than neatly, leaving gaps for frog-sized bodies. Driftwood, bark and a few broken terracotta pots laid on their sides all add to the effect.

If you keep a compost heap, you already have a wildlife hotel. Slow, cool heaps built from alternating layers of greens and browns stay damp and crawling with worms, slugs and beetles — exactly what a hungry toad wants. Leave one side of the heap undisturbed over winter so anything hibernating inside isn't disturbed by turning.

Dry stone walls and stacked bricks serve the same purpose, and their nooks are excellent for overwintering ladybirds, which will repay you by clearing aphids from your broad beans come June.

The Hedgehog's Night Patrol

Hedgehogs are the great slug destroyers of the UK garden, but their numbers have fallen sharply in recent decades, largely because gardens have become too tidy and too fenced. If you can do one thing, make a hedgehog highway: a 13cm square gap at the base of a fence panel, or a small tunnel beneath a gate. Neighbours doing the same create a connected route through several gardens, which is what a hedgehog needs to forage across a decent territory.

• Never use slug pellets. Metaldehyde and ferric phosphate both harm hedgehogs and the creatures that eat the poisoned slugs.
• Check before strimming or mowing. Hedgehogs rest in long grass during the day; a quick walk-through first prevents awful accidents.
• Leave a shallow dish of water. Hedgehogs get desperately thirsty in dry spells. A saucer of water at ground level is more useful than any food.
• Build a hedgehog house. A simple wooden box with a 13cm entrance, tucked under a shed or behind a shrub and filled with dry leaves, makes a safe hibernation spot.
• Cover drains and ponds. Or ensure the pond has that escape ramp mentioned earlier.

Meat-based cat or dog food and a bowl of hedgehog kibble are fine as an occasional supplement in autumn, but never bread and milk — it causes serious digestive problems.

Planting a Quiet Corner

Wildlife needs somewhere the rake and the strimmer never reach. Pick a corner of the plot, ideally against a hedge or fence, and let it go a little wild. A patch of long grass, a few nettles and some native wildflowers will pull in the insects that frogs, hedgehogs and birds feed on.

Useful plants to tuck in around your pond and log pile include foxgloves, ox-eye daisies, yarrow, comfrey and borage. Comfrey in particular earns its keep: its deep roots draw up nutrients from the subsoil, and its leaves make an excellent potassium-rich feed for tomatoes and courgettes. Meanwhile, its flowers are a magnet for bees and hoverflies, whose larvae eat aphids by the hundred.

A shallow gravel tray or an upturned bin lid filled with pebbles and water gives insects somewhere to drink without drowning, and a small pile of sand or bare earth helps ground-nesting bees.

Keeping It Working Through the Year

The main thing is to leave well alone. Resist the urge to tidy the log pile in February, to clear the pond in autumn, or to cut the long grass before the end of winter. Frogs, toads and hedgehogs all hibernate in exactly these places, and disturbing them in cold weather is often fatal.

If the pond silts up, clear it gently in early autumn with a rake, leaving the debris on the edge for a day so any creatures can crawl back in. Top up with rainwater rather than tap water. Add a fresh layer of leaves to the hedgehog box each autumn. And keep the gap in the fence clear, however tempting it is to block it.

Do these small things and by next spring you will notice the difference: fewer slugs on the hostas, more birds on the fence, and the satisfying sight of a frog sitting patiently by the salad bed, waiting for dinner to walk past.