How do I get rid of them? I have had a problem with my squash plants for a few years now. I am guessing that the insects lay eggs from year to year...
Garden Mites Killed My Squash Plants
Certified GKH Gardening Expert
Have you made a positive identification on the soil mites?
If you are dealing with mites it may be due to decaying material in the soil.
You may want to explore the possibility that it is another issue since you are having issues year to year.
Here are some links with some information on possible diseases, soil sterilization and crop rotation.