Centipedes Or millipedes infestation

Asked August 16, 2020, 1:38 PM EDT

Hi I inadvertently introduced these into my garden with leaf mulch two years ago. They are about an inch long and prolific. When I lift a pot there may be 50 of them. They do not seem to be harming much in the vegetable garden but eating some seeds and and rot vegetables. They mostly eat decomposing mater as expected. However last year they came into my basement and now I regularly find hundreds down there. It is not moist down there and it looks like they just go down there when it is very hot or wet outside and then die. I have tried to seal up the basement but I have a very old house and it’s not possible to do much more. So I would really like to get the balance of them in the garden back to a more reasonable level and hope to Have fewer in the house. I realize some of my aversion is because they are gross, but also I’d like to have a balance of critters in the garden again. Thanks so much for any help.

Multnomah County Oregon

1 Response

The creatures in your images are millipedes. They thrive in moist/wet places and, as you've already experienced, they sometimes come indoors. The two prime conditions for indoor invasions are when it's very wet, or hot and dry, outdoors.

Populations are often particularly high in shady gardens and where firewood, groundcover plantings, or an organic mulch, comes up to the foundation and/or rests against the siding.

In vegetable gardens, millipedes are often helpful in that they are cleaning up decaying organic debris such as leaf litter, decaying seeds, or over-ripe (or rotting) fruits.

One suggestion is to create an airspace between the structure and shrubby plants by pruning plants.

Another helpful strategy is to clear a strip 18-inches wide at the base of the house and, then, create a plant-free, also organic mulch-free, zone of gravel.