Before the First Freeze
What do you do when it looks like the growing season might come to a halt? Many times, if you can pull your plants through that first frost or light freeze, there will be several more frost-free weeks before winter arrives to stay.
For a light frost: Frost, which forms on plants’ leaves — just as it does on car windshields — during clear, still, cold weather, can disfigure or kill plants, so take precautions even when temperatures are expected to fall only into the high 30s. Covering plants with lightweight nursery frost cloth or old sheets can gain several degrees’ worth of cold protection. Move container plants under the cover of porches or beneath eaves.
For an actual freeze (32 F or below): Protect hardy plants (e.g., chrysanthemums in bloom; leafy and root vegetables) with lightweight nursery fabric. You’ll also gain several degrees of protection when you use those frost cloth fabrics to cover tender annuals like tomatoes or marigolds. Freeze-sensitive annuals can be protected from hard freezes by covering them with plastic suspended away from their leaves. Provide supplemental heat to keep temperatures above freezing beneath the cover. Do not allow plants’ leaves and flowers to touch the cold plastic.