[gamin]

Spores are absolutely everywhere and will germinate when the conditions mentioned by Hugh R are met. The only thing you can control is the moisture. If you install a dehu in your shop be sure the area is well sealed off from outside air or you will be drying that outside air. The dehu will run all the time with the consequent high electric bill and worn out early dehu. It is worth the money to get a good commercial grade dehu. The units sold by the box stores are crap and will not last.