Watered believe it or not.  The best solution is to WATER with an oscillating sprinkler BEFORE morning.  Watering like this actually slows the already frozen cells in thawing.  Fast thaw is what kills most plants or plant material subjected to a freeze or frost.  Watering slows the thawing down.  Healthy plants will be able to recover.  So yes, water them.  Get up in the dark mornings to check your garden for freezing.  If there was a freeze and you've got frozen plant material start watering.  Seriously, this slows the thaw process down so that there are less plant cells bursting when those cells go from frozen to thawing.[![potato plants after a night of freezing][1]][1].  I barely got out there to water but only the tops froze.  Plenty of foliage to continue to make potatoes.  I just lopped the ruined foliage off.  


  [1]: https://i.sstatic.net/TtrBW.jpg