Building a Simple Bug Hotel from Garden Materials

Not every wildlife project needs a trip to the garden centre. A decent bug hotel can be built from what is already lying about — a couple of pallets, a bundle of old canes, some dry leaves and a cracked terracotta pot. Put it together with a bit of thought and it will earn its place within a season.

Why a bug hotel earns its keep

The UK is home to roughly 250 species of solitary bee, and almost none of them nest in hives. They need small, sheltered cavities: hollow stems, old beetle holes, gaps in mortar. Ladybirds, lacewings and earwigs are looking for somewhere dry and tucked away to sit out the winter. A well-built hotel offers all of that in one small footprint.

It will not fix everything. A bug hotel is no substitute for a hedge, a patch of long grass or a pond. But it does something a wildflower border cannot — it gives insects somewhere to nest and shelter, which is often the limiting factor in a tidy suburban garden. Build it properly and you will see mason bees sealing up tubes with mud by April.

Choose a spot insects will actually use

Position matters more than carpentry. Get this wrong and the hotel will sit empty for years.

• Full sun for most of the day. A south or south-east facing wall, fence or shed is ideal. Solitary bees need warmth to become active.
• Shelter from wind and driving rain. Avoid an exposed corner or anywhere that catches the prevailing south-westerlies.
• At least a metre off the ground, on bricks, blocks or sturdy posts. Damp rising from soil is the single biggest killer of overwintering insects.
• Near flowers and a water source. Mason bees need mud for sealing nest tubes, so a damp patch of bare soil within a few metres is a real bonus.
• Away from bird feeders and bird boxes. Tits will happily pick off emerging bees.

Build the frame from pallets

Two standard pallets stacked and fixed together give you a solid, free structure. If you only have one, stand it on its side and brace the back with timber offcuts. Use clean, untreated wood — pallets stamped HT (heat treated) are fine, but avoid any that have carried chemicals or been left to rot.

Keep the whole thing under a metre tall. Anything taller becomes unstable and harder to inspect. Slip bricks or concrete blocks between the layers to create a few larger voids, and screw a scrap of roofing felt or a piece of old slate over the top as a cap, overhanging the front by a few centimetres. That overhang, not the filling, is what keeps the rain out.

Fill from the bottom up, packing materials tightly so nothing shifts. Gaps let in draughts and predators; tight bundles stay dry and warm.

Filling the rooms

• Hollow canes, 8–10mm across. Bamboo, elder or hogweed stems cut into 15cm lengths. Bundle them tightly with the open ends facing out and tilt the bundle very slightly downwards so rain runs off. Smooth any splintered ends — torn fibres trap wings.
• Drilled logs. Bore holes 3–10mm wide and about 10cm deep straight into the side of a log, across the grain rather than into the end, which splits. Leave the bark on.
• Dry leaves and straw. Loosely packed into a slatted box or a section of the pallet. Ladybirds, lacewings and earwigs all overwinter in leaf litter.
• Broken terracotta pots. Fill with dry grass and nestle them in upside down, leaving gaps around the rim. Excellent for ladybirds.
• Bark, dead wood and stones. Stacked at ground level for beetles, centipedes and the occasional frog or newt.
• Corrugated cardboard. Rolled into a tube or slotted into a gap, it is a favourite of lacewings.

Skip plastic bottles, glass jars and anything sealed. Insects need ventilation, and a sealed container becomes a mouldy death trap.

A word on solitary bees

Most of your visitors will be red mason bees, emerging from March, followed by leafcutter bees in early summer. The females lay eggs in the tubes, seal them with mud or chewed leaves, and the new adults stay inside until the following spring. That is why you must never move or clean the hotel between autumn and spring — you would be throwing out next year's bees.

A few tubes will be lost to parasites such as the ruby-tailed wasp, which is normal and part of a functioning garden. Do not panic and do not reach for sprays.

Keeping it healthy through the year

Check the hotel in autumn and make sure the roof is still shedding water and the frame has not shifted. Top up dry leaves if they have gone soggy, and resist the urge to tidy the bed around it — fallen leaves are part of the habitat.

Every second or third spring, once the mason bees have emerged, replace any canes that look damp, blackened or blocked. Reuse the rest. Then step back and leave it alone. The best bug hotels are the ones that are quietly forgotten about for most of the year.