Building a Bee Hotel That Actually Works

Red mason bees start appearing from late March, with the first males on the wing from early April in most of the UK, and they spend their entire adult lives, often only six to eight weeks of it, searching for a cavity to nest in. A bee hotel put up in April is competing for occupants with every hollow stem, old nail hole and crumbling wall cavity already in a garden; a bee hotel put up in May has missed the first wave of house-hunters entirely, because a female mason bee that has already found and sealed a nest elsewhere isn't coming back to check a new one.

Leafcutter bees follow later, from late spring into summer, so a hotel hung in good time isn't wasted if the mason bees pass it by, but the mason bees won't wait. Emergence is temperature-driven: colder overwinteringKeeping a plant alive and intact through the cold months, whether left outdoors, moved under cover, or stored dormant. Full definition → conditions delay it, so a slow, cold Scottish spring can push actual emergence closer to the later end of that window rather than the earlier one, a reason to have the hotel up in good time regardless, rather than banking on the earliest possible date.

That means late winter to very early spring is the real deadline, not April itself. Get a hotel sited and secured while the garden still looks dormant, so it's already weathered-looking and in place before the first males emerge.

Diameter matters more than anything else

A tube's diameter decides which bee, if any, uses it, get it wrong and a hotel can look full of activity while doing almost nothing for the species it was meant to help:

A hotel packed with only one diameter attracts only one kind of bee; mixing sizes gives the widest range of species something usable, and holes much wider than the table above mostly go unused. To work out which bee has actually moved in, once one turns up, see the beneficial wildlife guide's solitary bees entry.

Length matters almost as much as width. Tubes need to be around 15cm long with a closed or dead end, not open at both ends. Solitary bees lay female eggs at the back of a tunnel and male eggs nearer the entrance, so a tube that's too short skews the ratio toward males, and an open-ended tube isn't recognised as a nest cavity at all, since nothing in nature looks like it.

What the tubes are actually made of

This is where most commercially sold bee hotels fail. Many garden centre hotels are built from resin-bonded or varnished tubes packed too densely to inspect or replace: moisture condenses inside the sealed tubes with nowhere to go, and that damp becomes the growing medium for fungal mould and mite infestations, which then spread from one packed-in tube to the next.

Scotland's cooler, wetter growing season means sealed or non-porous tubes spend more days damp than they would further south, which is a reason to lean toward the more breathable materials, untreated reed, bamboo, hollow stems, or paper liners that can be swapped out, rather than solid plastic or resin tubes.

Building the frame

A simple wooden frame, open on one side, holds the tubes in place: a plank of untreated, sustainably sourced timber around 1.5cm thick works for the box itself, with a solid back so no tube is open at both ends. Pack the tubes in tightly enough that they don't rattle loose, mixing diameters rather than filling each row with one size.

A roof with a genuine overhang, deep enough to keep driving rain off the tube openings, matters more than the material it's made from, the same damp-tube problem as the materials above, caused by weather rather than the tube itself, and worth taking seriously given how much rain a Scottish garden gets through the year. A flat or minimal roof, one of the most common faults in cheap commercial hotels, leaves the tube ends exposed to weather side-on.

Siting: sun, shelter, height

Face the hotel south or south-east, so it catches the morning sun, solitary bees are cold-blooded and need that early warmth to become active enough to forage. Position it somewhere sheltered from driving rain and wind, under an eave or wall overhang if possible, not in the open. Fix it securely: a hotel that sways or swings in wind is a hotel bees won't use. Raise it well off the ground, at a height where it's easy to see and check without disturbing it, rather than leaving it low down where it's more exposed to damp, slugs and ground predators.

A hotel also needs somewhere to forage. Occupancy depends on the whole garden having pollen-rich flowers in bloom through Scotland's March-to-October pollinator season, not just around the hotel itself, and free of pesticides, with willow and other early-flowering plants mattering particularly for the first mason bees out in spring.

Where a species is genuinely scarce in an area to begin with, no amount of correct diameter, siting or forage will produce activity, the red mason bee, the most likely first occupant further south, is itself uncommon in Scotland, and which solitary bees are actually present locally is worth checking in the beneficial wildlife guide's solitary bees entry before assuming a quiet hotel means something was done wrong.

Seasonal maintenance: the part cheap hotels skip entirely

A bee hotel isn't a one-off purchase; it needs yearly attention, and a hotel that can't be opened for that attention will eventually spread disease among its own occupants rather than support them.

Most garden centre hotels can't go through any of this, because they're built with sealed resin tubes and glued-in cardboard with no removable liners, a design fault, not a maintenance failure on the owner's part.

Common questions

Sources