crawl space in 1840s home

[cmoore]

I have an 1840s home and my inspector recommended installing a vapor barrier in the dirt floor crawl space as well as doing closed cell spray foam on the ceiling of the crawl space. I am wondering how necessary/important this is? I also have read a lot of information on how old houses need to breathe and wonder if a vapor barrier would harm the home in any way. Particularly it seems like mold would potentially grow under the vapor barrier. Look forward to hearing people's thoughts!

[pgwood]

We have an 1860 log home with a crawl space under it. Thirty seven years ago when we moved in it was damp and slightly muddy. Due to its slope I was only able to put a moisture barrier of plastic over about 80% of the crawl space. Today it still has the same plastic and it seems very dry but i did install a vent on the shallow side and a vent in the crawl space door which I open in the summer and close in winter. I have not insulated it but I repointed the stone foundation because of the drafts.