How do I protect herbal plants from frost?

I live in Houston and we get occasional frost too. We simply cover with old blankets.

Try plastic bags? Brown paper bags...my dad used them alot

Where in CA? I use tomato cages or something similar and cover with paper or plastic with breathing holes depending on the plant.

I lived in Las Vegas for years and we would get the once a year frost or a downright freeze, but I never lost anything in my herb garden because I covered the plants with old quilts because the batting in the center of the quilt acted as insulation just like the insulation in your walls. You can find old quilts and blankets in the thrift stores if you don't have any on hand. Good Luck