If you live much lower than the surrounding hills, particularly in a valley or otherwise sheltered place, you are much more likely to cop a touch of ground frost than somewhere higher up and less sheltered.
Are they too tall now to earth up to cover them? That's by far the easiest and possibly even the quickest way and it has to be done at some point in the future anyway.
Other than that the decision has to be between you, your location, and the Met Office!