Mold prevention in a crawl space. Lime?

I have a year old house in North carolina that I recently found mold growing under the plastic in the crawl space. The builder is going to treat everything but isn't planning any type of prevention. I am now going to leave the vents open in the winter (I closed them last winter and opened in the summer per their recs) and was considering spreading lime since it theoretically makes the environment less prone to fungus ie mold. Does my theory hold water? I know I can get a fan system or dehumidifier (my builder said this will dry out the wood) but I was looking for a cheaper alternative to try first. Thanks.!

Mold prevention in a crawl space. Lime?
mold only grows in the presence of moisture. Is the mold inside the plastic by the insulation? If so, it must not be the proper thickness of plastic or it is not sealed properly. The plastic should be tapped at every joint and seam. It should also be to the ends where it meets the exterior walss and be taped and sealed there as well. The builder may have used the improper thickness and may not have taped the plastic vapor barrier correctly. No air should be able to penetrate this barrier. I would also have caulked around the perimeter of the barrier where it meets the walls. How is he going to treat it? If it is behind the barrier he would have to remove the barrier to get to it. Is he going to do that? If so have him replace it with a thicker plastic and tape everything including the spots where the staples go through.
Reply:I had the same problem, I removed the plastic and sprayed everything with a household bleach solution and let it air out for a week and replaced the plastic with new. As long as you have the plastic down, it will be susceptible to mold.