A Simple Guide to Building a Bug Hotel

Why a bug hotel earns its place in the garden

Our gardens, allotments, orchards and field edges add up to an enormous patchwork of habitat, and much of it is tidier than the wildlife would like. A bug hotel — sometimes called an insect tower, or simply a bee board — is a stack of recycled odds and ends that gives small creatures somewhere to nest, shelter and overwinter. Built carelessly, it becomes a damp pile of rotting rubbish. Built properly, it will hum gently on a warm morning and quietly work away at your aphids all summer.

Solitary bees are the stars of the show. Unlike honeybees, they do not live in colonies: each female finds her own tunnel, provisions it with pollen and nectar, lays an egg and seals it up. Red mason bees and leafcutter bees are common visitors to British gardens, and they are excellent pollinators of apples, pears, soft fruit, runner beans and tomatoes. All they need from you is a dry, sunny length of hollow stem or a drilled block of untreated wood.

The other guests are just as useful. Ladybirds and lacewings overwinter in dry, sheltered crevices, and their larvae eat greenfly by the dozen. Ground beetles and rove beetles patrol the soil for slug eggs and small pests. Earwigs, much maligned, tidy up soft-bodied insects overnight. And a hotel with a chamber of loose bark will often be adopted by a bumblebee queen searching for a dry spot to start again in spring.

Choose the spot before you choose the design

Siting matters more than carpentry. A bug hotel in deep shade will stay cold and clammy, and damp tunnels grow mould that kills developing larvae. Aim for a warm, sheltered wall or fence that faces roughly south to south-east, so the entrance holes catch the morning sun and dry out early.

• Height: mount it at least a metre above the ground, on a wall, fence post or shed. A paving slab on top of stacked pallets works well for a ground-level version.
• Shelter: avoid the side of a building that takes the prevailing wind, and keep clear of dripping gutters, downpipes and water butts.
• Stability: fix it firmly. A wobbling hotel shakes the contents and discourages nesting.
• Surroundings: put it within a few metres of flowers. Lavender, borage, comfrey, foxgloves, wild marjoram and sedum are all reliable, and a shallow dish of water with pebbles in it will be well used.

Scavenge your materials first, then build

The best bug hotels cost nothing but an afternoon. Have a wander round the shed and the woodpile before you start, and let the materials dictate the shape of the thing.

• For the frame: an old wooden pallet or two, a rejected apple crate, a length of weathered scaffold board, broken bricks, roof slates, a cracked terracotta pot.
• For the chambers: bamboo canes, spent sunflower and teasel stems, dry straw, dry leaves, loose bark, log offcuts, wood shavings, corrugated cardboard, a block of untreated hardwood.
• Avoid: treated or painted timber, plastic bottles, glass, anything already damp or mouldy, and anything held together with rusty wire. Peat-based materials have no place in a wildlife project.

Building the frame

A simple, sturdy design is four pallets stacked and screwed together, with a back panel of exterior ply or old floorboards and a pitched roof made from overlapping slates or a sheet of roofing felt. Give the roof a generous overhang — 10cm or so on every side — because keeping rain out is the single most important job it does. A hotel roughly 60cm wide, 40cm deep and 60cm tall is plenty for a domestic garden and will hold six to eight good chambers.

Divide the inside into compartments using bricks, roof tiles or timber battens laid on their sides. Each compartment should be open at the front but closed at the back, so there is no through-draught. Leave the very bottom chamber open to the ground if you can, and fill it with dead wood and leaf litter for beetles.

Filling each chamber for its guest

Pack every compartment tightly — loose, rattling material shelters nothing. Keep each chamber to a single material, as different insects want different things.

• Solitary bees: a block of untreated hardwood, drilled with holes 6–10mm across and 100–150mm deep, with the holes smoothed and facing slightly downwards. Or a bundle of bamboo canes cut into 15–20cm lengths with the open ends facing out.
• Ladybirds: a tight bundle of dry hollow stems, or stacked pieces of loose bark, kept thoroughly dry.
• Lacewings: a roll of corrugated cardboard slotted into an old tin or tube, with the flutes facing outwards.
• Beetles: log offcuts, bark and dry leaf litter in a ground-level chamber.
• Earwigs: an upturned terracotta pot stuffed with straw or wood shavings, resting on top of the frame.

Looking after it through the year

Once it is up, the chief task is to leave it alone. Resist the urge to tidy it in autumn — the whole point is that it stays put while insects use it as winter quarters. Check that the fixings are still firm after gales, and clear any leaves that block the entrance holes.

Bee tubes and drilled blocks should be cleaned or replaced every couple of years, in early autumn once the adults have emerged. Hollow stems can simply be swapped for fresh ones; a drilled block can be gently brushed out and left to dry in a shed for a week before going back up. Add a little fresh material each spring, and let the whole structure weather to a silvery grey. A slightly scruffy bug hotel in a sunny corner is one of the cheapest, kindest things you can do for the countryside around you — and it takes an afternoon.