Does MN require a grace period before impsoing a late fee?

[John Woodrich]

I inherited some leases and they all provide for payments being due on the 1st of the month and that a late fee will be assessed if they have not paid by the 5th.  So inherently they all normally pay on the 5th....

I need to present new leases anyhow but I can't find anything that stipulates a grace period is required.  Can anyone confirm whether MN requires a grace period or whether I can charge a late fee on the 2nd?  

Thanks,

John