if they dont seem to be doing any harm, are you sure they are mites?
without a pic they could be anything, possibly something harmless like springtails
if its commercial weed with seeds in
somethin probably hermied
i imagine most of it is grown from clones???
you can get good quality genetics quite cheap
look at mandala or nirvana seeds
but if all u got is bag seed
and dont wanna commit urself to this wonderful hobby
just go for it...