Answer: I suspect your palms already had a population of mites before you brought them home. You may be able to avoid this problem by hosing the plants off thoroughly before bringing them indoors. As soon as you bring a new palm home, use a fine spray from a hose nozzle and carefully spray every square inch of the trunk and fronds. You'll wash off the mites plus any dust. After a week, take it outdoors and hose it off again (this will wash off any mites that hatched after the first shower). And, because the third time's a charm, wait another week and take it outdoors for another thorough cleaning. If any spider mites survive after that..... they're coming from other plants in your home!
Good luck with your new palm.
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