Cold Weather and Your Plants

Name: _______________________________________
Date: ______________
Cold Weather and Your Plants
Why is cold weather bad for your plants?
Like other living forms, plant cells contain water and water can freeze. Scientists suggest that
during a frost, if water in plant cells freezes, it can damage cell walls because solid ice takes up
more space than the liquid from which it was frozen. The crystals then rupture the tough cell
walls and, when the ice melts, any liquid drains out, dehydrating the plant. Soil can also freeze,
which threatens plants' abilities to get nourishment.
Are some cold conditions worse than others? Yes. Key factors to cold damage include:
Temperature –Duration –Climate conditions - Terrain – Soil - Stage of growth
1) Lower temperature = more damage
-- The colder it is, the more damage your plant will sustain.
2) Longer time at low temperature = more damage
-- The longer your plant is subjected to cold conditions, the more extensive the damage
3) Clear night = more damage
-- If it’s a clear night, your plants will not have the benefit of a cloud “blanket” which keeps the
air temperature warmer.
4) Low areas in landscape (terrain) get colder = more damage
-- Cold air is heavier than warm air and sinks. If you have slopes in your yard, plants in low areas
will suffer more damage than those in higher areas.
5) Light soil = more damage
-- Darker soil will retain heat longer than lighter soil and thus help your plants retain heat.
6) New blooms = more damage
-- Fresh young blooms are tender and easily damaged by frost. If your plant has just sprouted
new blooms, it will sustain more damage.
Is it true that watering your plants when it gets cold will help protect them?
Yes. When water from sprinklers turns to ice, the heat released protects the plant from injury. As
long as a thin layer of water is present, on the bloom or on the ice, the blossom is protected. This
is important. It's not the layer of ice that provides the protection. It's the water constantly freezing
that keeps the temperature above the critical point.
Can I cover my plants to protect them?
Yes. You can cover cold-sensitive plants like tomatoes & peppers but if it’s very cold for a long
time, it won’t be enough. To be safe, harvest as much fruit from your plant BEFORE it freezes
and allow it to fully ripen indoors.