Autumn is the practical maintenance window for garden insect hotels: breeding is over, temperatures are falling, and damp nesting material has time to dry before frost. The job is less about scrubbing and more about correcting the failures that shorten a habitat’s useful life: poor placement, trapped moisture, winter disturbance and loose fixings.
Move the habitat out of full sun
Many insect hotels fail because they are treated as ornaments and fixed to a south-facing wall. In late summer a small wooden box in direct sun can run several degrees warmer than the surrounding air, stressing larvae and pushing solitary bees away from the nesting tubes. A wildzy habitat hung under an eave or against an east-facing fence gets morning warmth without the afternoon bake. Dappled light and rain shelter matter more than a decorative position.
Remove damp tubes, keep dry ones
Moisture is the quiet killer. Solid blocks drilled with smooth holes trap condensation, and capped tubes cannot drain; reed and bamboo sections can harbour mould after a wet August. Check the open ends: dry, brittle material can stay, while blackened or soft tubes should be pulled out and replaced. Removable nesting sections make this a five-minute swap rather than a rebuild, and they let you inspect the back wall for damp patches before winter.
Do not clean with bleach or soap
Insect hotels are not bird feeders. A bleach solution or household detergent leaves residue inside porous wood and reed, and the next generation of leafcutter bees will contact it directly. Use a dry brush for loose dust and a damp cloth on the exterior only. If mould has spread through a fixed block, replace the block rather than treating it; the cost is lower than losing the habitat’s occupants.
Leave undisturbed corners alone
The tidy instinct is the problem. Leaf litter, hollow stems and loose bark around the base of an insect hotel are not clutter; they are overwintering cover for beetles, spiders and queen bumblebees. Clearing them in October removes the species that make the habitat work. Rake leaves away from paths, then pile them within a metre of the hotel and leave the pile alone until late spring.
Fix loose fixings before the first frost
A wobbling hotel rubs against its mount and opens gaps at the back, letting rain in. Tighten screws, replace rotten hanging wire and check that the roof overhang still sheds water. One small repair now prevents a wet winter from turning a useful habitat into a mould trap. That is the whole autumn routine: shade, dry tubes, gentle cleaning, undisturbed cover and firm fixings.