Seal it. In this climate, venting a crawl space in summer pulls humid outdoor air onto cool surfaces and condenses it, which is the opposite of drying. Current practice is a sealed, insulated crawl with a ground vapor barrier.
More detail
Vented crawl spaces were standard for decades on the theory that outdoor air dries the space. In a humid summer climate that reasoning runs backwards, and it is why so many vented crawls in Greater Columbus and Central Ohio are damper than the outdoors. The physics. Summer outdoor air here is warm and holds a lot of moisture. Crawl space surfaces sit near ground temperature, which is much cooler. Push that air across those surfaces and it drops below its dew point, and the moisture condenses on framing, ductwork, and the underside of the subfloor. The vents deliver the water rather than removing it. The musty smell in the house above is that moisture, carried up by the same stack effect that moves everything else. Encapsulation reverses it. A heavy polyethylene ground vapor barrier, typically 10 to 20 mil, is laid over the earth and sealed at seams and up the foundation walls. The vents are closed and sealed. Insulation moves from the floor joists to the perimeter walls, which brings the crawl inside the conditioned envelope. A dehumidifier or a small conditioned air supply controls what remains. What you get: no more summer condensation, warmer floors in winter, no ground moisture evaporating into the house, and a space where ductwork is no longer running through a hostile environment. What to check first. Encapsulation is not a water management system. Standing water, a spring, or bulk water entry has to be handled with drainage and a sump before sealing anything, or the barrier traps water under it. And any combustion appliance venting into that space needs review before the space is sealed. Cost in this market runs meaningfully above simple floor insulation, and the payback shows up in comfort and in avoided moisture damage as much as in the heating bill.