Why Are There So Many Spiders Around My Windows?

Light Brings the Prey

Light escaping through glass at night draws flying insects to it from a considerable distance. Moths, midges, flies and lacewings gather at the pane, and the spiders set up where the food arrives.

That is the main reason, and it explains the pattern people notice: the worst windows are the ones with a lamp or a television behind them, and the worst outside corners are the ones nearest a porch or security light.

The Frame Gives Them Structure

A web needs anchor points. A window reveal, the corner of a frame, the gap between a frame and a sill, and the underside of a window head are close to ideal — two or three surfaces meeting at right angles, sheltered from wind and rain.

It is also somewhere nobody disturbs. Most people clean the glass and never touch the reveal or the top corner of the frame, so a web there survives indefinitely.

Warmth and Shelter

A window recess is out of the weather and slightly warmer than the open wall, especially on a south-facing elevation. In autumn that matters, and it is part of why spider activity around windows rises sharply in September.

Trickle vents, gaps in old frames and the gap under a sliding door also give a route in, so the window is often the boundary between the outdoor and indoor populations.

What Actually Reduces It

Change the lighting first. Move an outside light away from the window or door, use a warmer-toned bulb, and put it on a sensor rather than dusk-to-dawn. Draw curtains or blinds in the rooms that face the worst corners.

Then clean the structure rather than the glass: brush out the reveals, the top corners and the underside of the head, outside as well as in. Removing webs and egg sacs regularly does more than any spray, because it removes the anchor and the next generation together.

Cut Back What Touches the Building

Ivy, shrubs and climbing plants against a wall are both harbourage and a bridge to the window. Trimming them back from the elevation makes a noticeable difference over a season.

If it is still persistent after all of that, a treatment is £180 for the first room and £60 for each additional one. But if it is late summer and you are seeing big wandering males for two or three weeks, that passes on its own and we will say so.