Smith County Horticulturist Some can withstand prolonged spells
of below freezing temperatures, while others bite the dust with
only a slight exposure to a freeze. A couple of principles
should be kept in mind when trying to protect marginally hardy
plants from cold, or to extend the tomato or pepper harvest by
covering plants. First, plants do not generate their own heat.
So, any warmth absorbed from the energy of the sun will be
quickly dissipated after a few hours of below freezing
temperatures, especially if it is windy. The most practical type
of plant protection is from a radiation-type freeze. This
happens on a still, cloudless night after a sunny day when
plants and other surfaces release back into the atmosphere any
heat energy absorbed from the sun during the day. Overhead
branches and the eves of a house can trap some of this escaping
heat, creating a mini-environment that is a couple of degrees
warmer than just a few feet away in the open. Floating row
covers are commercially available for coverin