Why solitary bees need a helping hand

Of the roughly 270 bee species recorded in Britain, only the honeybee and around two dozen bumblebees live in colonies. The rest are solitary. Each female works alone, finding or excavating a private tunnel, laying her eggs inside it, sealing it up and never coming back. Roughly a quarter of our solitary bees nest in hollow plant stems or old beetle holes in dead wood, and those are exactly the things tidy gardens tend to remove.

A bee hotel is simply a replacement for what we have cleared away. Done well, it will be used by red mason bees, leafcutter bees and a host of smaller species, all of them excellent pollinators of fruit, soft fruit and garden flowers. None of them guard a nest, none of them swarm, and they are extremely reluctant to sting. You are not keeping bees so much as offering bed and breakfast.

Choose the site before you choose the timber

Placement decides whether your hotel is occupied or ignored. Solitary bees need warmth to become active in the morning, so face the hotel between south-east and south-west, with the entrance catching the early sun. Mount it at least a metre off the ground — ideally somewhere between one and two metres — on a wall, fence or shed that stays firm.

• Shelter it from driving rain, under deep eaves if you can.
• Fix it rigidly. A hotel that rocks in the wind will be abandoned.
• Keep it away from bird feeders and tit nest boxes. Blue tits will happily pick off emerging bees.
• Avoid deep shade, north-facing walls and anywhere that stays damp.

Use untreated wood and natural hollow stems

Materials matter more than design. Tanalised, pressure-treated, stained or painted timber can leach chemicals into the nest tunnels, so use untreated hardwood such as oak, ash or beech, or a decent untreated softwood block. Inside, aim for something close to what a bee would find in the wild.

• Drilled blocks: use dry wood and drill across the grain, not into the end grain, which splinters. Holes should be 2–10mm across and 100–150mm deep, with a closed back. Smooth the entrance with a light sanding so fragile wings are not torn.
• Hollow stems: bamboo, teasel, hogweed, bramble and elder all work. Cut them into 15–20cm lengths, cutting just beyond a node so one end is naturally sealed.
• Pack them tightly. Loose stems let in light and give parasites a way through. A short length of drainpipe or an open box works well as a container.
• Skip plastic straws, glass jars and flimsy cardboard tubes. They either trap moisture or fall apart within a season.

Building a simple, solid hotel

A basic open-fronted box is all you need. Make it roughly 25cm tall, 20cm wide and 15cm deep, with a solid back board and a roof that overhangs the front by about 5cm to throw off rain. Leave the front completely open — mesh or wire can trap bees and will not keep anything out.

• Fill the box with a drilled block on one side and tightly packed stem bundles on the other, so different species have options.
• If the box is open to the weather, mount it with a very slight downward tilt so water runs off rather than sitting in the tunnels.
• Secure it with screws and brackets rather than string or wire, which sag and shift.
• Put it up in early spring, from March onwards, so it is ready when the first females emerge.

Care, cleaning and the golden rule

Here is the rule that matters most: once the hotel is occupied, leave it exactly where it is. Female solitary bees memorise the position of their nest site, and bees that emerge from a moved hotel often fail to find their way back to it. Do not relocate it to a shed for winter, do not take it indoors, and do not turn it round to face a different way.

Maintenance is minimal. Keep it dry, never hose it down, and never treat the wood with anything. In late summer, after the bees have emerged and the tunnels are empty, you can gently clean wooden blocks with a bottle brush or replace spent bamboo stems — roughly every two years is plenty. If you find tunnels blocked with mud or chewed leaf pulp during the nesting season, that is a bee at work, not a problem.

Common mistakes to avoid

• Moving an occupied hotel, even a short distance.
• Facing it north or hanging it in permanent shade.
• Using treated, painted or varnished timber.
• Drilling holes wider than 10mm, which attract nothing useful.
• Hanging it beside a bird feeder or tit box.
• Buying a mass-produced hotel full of splintery softwood and plastic tubes — build your own and you will get far more tenants.

Get these details right and a well-sited hotel will fill within a single season, then keep paying you back in better-pollinated apples, runner beans and raspberries for years.