Preventing Wasp Nests: The Spring Check
By Wespenprofis.ch · Reviewed by:Fachbewilligung Schädlingsbekämpfung VFB-S · Updated: 3 July 2026
At a glance
In spring, young queens search individually for a sheltered nesting site. Check roof overhangs, roller shutter boxes, garden sheds and cavities for entry points, seal these early with fine mesh or sealant, and inspect your house regularly during April and May.
Why spring is the decisive moment
Only mated young queens survive the winter, usually in crevices, deadwood or gaps in masonry. From April onwards they become active and search individually for a sheltered cavity protected from the weather in which to build a small starter nest. At this early stage there is no colony yet – only a single wasp is flying. That is exactly what makes spring the ideal time for prevention: if you make potential nesting sites unattractive or seal them off now, you will often prevent a large nest with hundreds of insects from forming later in the summer.
The walk-round: where young queens like to move in
Take a walk around the house and garden and check the typical weak points: roof overhangs and gaps between roof tiles, roller shutter boxes with gaps, vents without a mesh screen, garden sheds, bird boxes and compost heaps, as well as cavities in façade cladding. Old, disused mouse holes or holes in the lawn are also possible nesting sites for ground-nesting wasps. Small openings that a wasp can just squeeze through are enough.
How to seal correctly
Holes and crevices that are permanently unused can be sealed with sealant, mortar or fine-mesh insect screen. With vents that are still in use, you should not close the opening completely but instead fit a fine mesh screen in front of it so that air can still circulate. Check the roller shutter box regularly if you have not yet used it in spring. It also helps to clear away fallen fruit promptly and to cover compost, as both attract wasps and other insects – more on this in the guide Was zieht Wespen an.
When prevention comes too late
Despite a careful check, a nest sometimes forms anyway. If you spot a single wasp repeatedly flying in and out at the same spot, watch the place from a distance and, if in doubt, have it assessed by a professional rather than taking a look yourself. You can read the basics on how to behave correctly when you find a nest in the guide Wespennest gefunden – was tun. General tips for dealing with wasps in everyday life can be found in the pillar guide Wespen vertreiben, and advice specific to balconies and terraces in the guide Wespenschutz Balkon. Wespenprofis.ch removes an established nest properly and safely (/wespennest-entfernen).
Frequently asked questions
When is the best time to take preventive measures?
In spring, usually from April to early June. This is when individual young queens are looking for a nesting site, no nest has formed yet and openings can be sealed without any risk.
What is the best material for sealing possible entry points?
Fine-mesh insect screen, sealant or mortar are suitable for openings that are permanently unused. Vents that are still in use should be fitted with a mesh screen rather than sealed completely.
What if I already see a single wasp in the roller shutter box in spring?
It may be a young queen looking for a nesting site. Watch the spot for a few days; if a small nest starts to take shape, bring in a professional early on.