How to keep wasps out of birdhouses

Clean birdhouses every late winter. To deter wasps, rub a bar of unscented soap or wax on the inside of the roof.

Q:  I have a wren house I want to put out this spring. Previous houses I’ve put up had wasp nests, I have heard of applying wax to the inside of the roof but haven't tried it. Do you have other suggestions?

A:  One of the simplest and most effective tricks to prevent wasp nests in bird houses is to take a dry bar of plain, unscented soap and rub it across the inside roof of the birdhouse. You can also candle wax, paraffin wax, or beeswax onto the inside ceiling. Just like soap, the smooth surface prevents wasps from anchoring their nest.  Wasps have trouble attaching their papery nest material to the slick surface. Birds don’t mind it at all.  

Most importantly, avoid insect sprays inside birdhouses. They can harm birds and their chicks.

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Read our Q & As with Keith Funk answering common Colorado gardening questions here. See his website: gardenwiseguy.com and hear him on the Garden Wise Radio Show.