I was wondering will a temp of 4% to 5% cause a ground frost this week.
I'll assume you are speaking of temps of 4-5 Celsius. Whether this will cause frost depends on how humid the air is. It may also produce "freezing fog". I don't believe this will affect any but the most frost tender plants because the plant doesn't freeze, just the atmosphere. Covering a tender plant with a towel suspended on plant stakes will be adequate protection.