try diatomaceous earth and/or borax. both harmless (I consume both) but both work well against pests.
Mite not.
http://wholelifestylenutrition.com/natural-solutions/what-is-diatomaceous-earth/
Apparently not even food grade diatomaceous earth is meant for humans to ingest. But it is bad for bugs.
Diatomaceous earth is the best!! But once it’s damp, it’s useless, so I don’t know how helpful it is outdoors.