Preparing for a Freeze or Frost

Middle Tennessee and much of the south is expected to receive a freeze tonight.  We all know how damaging a freeze could be and we have no to look no further back than 2007 to see the results.  That year many gardeners lost trees like Japanese maples and crape myrtles due to the flow of sap in the trunks freezing overnight which then split the bark.  Unfortunately we can't alter the weather on demand so we have to prepare our gardens for the cold temperatures.

Tips to Protect Plants from a Freeze or Frost:

• Use plastic only if you can make sure the plastic does not touch the plants.  The cold will transfer through the plastic easily and anything that touches it will be damaged.  Support plastic with plant cages, stakes, or hoops of some kind.
• Cover with blankets, sheets, towels, or other cloth fabrics.  Covering will create an air pocket that will insulate your plants. Cloth fabrics do not transfer like plastic and are much easier to use.  Just lay them over the plant your want to protect!
• Be selective with your landscape plants.  You can't cover everything so pick out the most important plants in your garden to protect.  Fruit trees, expensive exotic plants, or any annuals you may have already planted should make your list. Native trees are better adapted to frosts and freezes and may not need protection.
• Make cloches to cover your plants from milk jugs, plastic bottles, or even plastic nursery pots. A cloche is a simple covering that creates a mini-greenhouse over a plant. Make sure your plants don't touch the plastic as mentioned earlier.

  

  Cloche made from plastic jug

• Water the plants ahead of time!  Strawberry and fruit growers will spray water over their plants and allow it to form into an ice covering.  This keeps the water inside the leaves of plants from freezing which is what causes the damage.
• Water the soil around your plants.  Water is a great heat sink and will help the soil retain more heat overnight which will result in warmer plants.
• Bring in potted plants indoors.  Potted plants will get at least 5 degrees colder than the ambient air temperature which can be very significant!  Get them in a garage or in the house until the outdoor temperatures improve.
• Set out jugs of water to warm in the sun near but not touching your plants.  They will absorb heat during the day then release it at night.  This may increase the temperature slightly near your plants.
• Use hardscaping as a heat sink near tender plants.  Bricks, rock, and asphalt will all absorb heat and will release it as temperatures cool off.
• Use a combination of the above. When the weather predicts temperatures as cold as they are saying there can be a lot of variation caused by microclimates.  A frost pocket or a shady hillside may be over 5 degrees colder than the predicted low so use a combination of approaches to protect your plants. 

You may not need to do all of these techniques to protect your plants but it is better to be safe than sorry. I always council people to plant tender plants after the last frost date and even wait 2 extra weeks just in case. That gives the soil time to warm up and gives a little bit of a safety cushion in case of another frost or freeze. What frost/freeze protection techniques do you use?