The best solution is to cure the problem, not just the syptomn. Moisture is the symptomn. The problem is moisture getting into the space in the first place.
First step, as Jim-ATS stated is stop ground vapor from entering by plastic on the ground. Also, verify that there isn't water run-off entering. Venting the crawl will probably worsen the situation. The ground is cooler than the air. Warm moist air coming in contact with it leads to condensation. Again preventing the moisture from getting there in the first place is the best course.