If you've already purchased some potted plants, you'll want to bring them inside for the night.
Environment Canada issued a frost advisory for Sarnia-Lambton on Thursday afternoon.
Meteorologists are expecting patchy frost overnight into early Friday morning.
"Temperatures are expected to drop to the near freezing mark overnight into early Friday morning. Cover up plants, especially those in frost-prone areas," the advisory said.
A similar advisory was posted in London-Middlesex, Chatham-Kent and Huron counties.