Reenactors tell me they get this question all the time. As the women work around the campfire, on-lookers ask whether their hems are wet. Costumed interpreters also hear this question as they work in kitchens. It’s related to the myth about burning being the most common cause of death for women in “the olden days” because of their long skirts catching fire (see Myth #2).
Generally speaking, only formal wear was worn so long that hems skimmed the ground. While skirt length in America has varied throughout the past four centuries according to fashion, working women (which is to say, most women) were more likely to wear skirts that were several inches above the ground. Even then, they might hike up the hem and tuck it in their waist to get the skirt out of the way. “During much of the eighteenth century,” writes textile curator Linda Baumgarten, “women’s skirts were long and the sleeves covered the elbows; yet a woman would readily push up her sleeves and hike up her petticoats while doing laundry or working in the dairy, and, when fashion dictated it, women would shorten their skirts to the ankles, as many did in the 1780s.”
Another point worth noting, as many reenactors have discovered from personal experience, is that natural fabrics that are common in historically accurate clothing–wool and linen–don’t burst into flame when they come into contact with fire. They smolder.
Just for fun, here’s an old poem (1568) by Sir Philip Sidney that mentions young women hiking up skirts to play sports!