I just kicked out the GF today and have already moved most of her crap to her folks house...  My guess is that, like everything she does, she'll drag her butt to remove the remainder of her possession in some far fetched hope of reconciliation....  My question is how long do I have to store her crap before it's legally considered abandoned?

https://www.revisor.mn.gov/statutes/?id=504B.271

Not sure if your situation would fall under this law though due to the relationship, may be best to contact someone.  Either way, I'd give a certified written notice that she should come pick up her items.

30 days, after official written notice of eviction.