[Arid_gardener] Covering plants in AZ winter

[Olin Miller]

----- Original Message ----- From: "Jean Pahlke" <jpahaz at hotmail.com>
Sent: Sunday, December 03, 2006 7:52 PM
> What is the best way to cover plants when the valley temperature gets
> close
> to freezing? I have been using sheets. This past week when the temperature
> hit freezing I experienced some damage to some young plants that had been
> growing from seed. They were covered with a sheet. Is plastic better?

===========================================================
The best protection is a frost blanket.  Comes in 12'x10' at most nurseries
or 12' wide any length from a roll at some nurseries or at various other
sizes by mail order..  Cotton bedsheets usually work for our light freezes -
use 100% cotton.  I would not use plastic.  Wherever plastic touches
foliage it is likely to freeze it.

Following is an excerpt from publication, AZ1002 Frost Protection at
http://cals.arizona.edu/pubs/garden/az1002.pdf

If you have access to the internet you might consider printing a copy, else
on can order a copy - call (602) 470-8086 for ordering information.

Olin Miller, Master Gardener Volunteer, Maricopa County AZ

               "Cover plants with cloth or paper (not plastic) to insulate,.
You can use
sheets or blankets for minimal. protection or use a frost cloth. A properly
applied frost cloth can protect plants at temperatures down to 30' F, some
down as low as 20' F depending on the fabric and the weave. Completely drape
tile plant from top all the way, to the ground. Do not allow any openings
for warmth to escape. 'This procedure will trap the heat radiating from the
soil and maintain a more humid atmosphere around the plant foliage.
Optimally, the drape will be supported by a frame which does not allow it to
touch. the foliage. DO NOT gather the drape around the trunk of the tree.
The goal is to trap heat being radiated from the ground, so ensure that the
drape touches the ground at least as far out as the drip line..

  If you use sheets or blankets, remove the coverings every morning when the
temperature under the covering warms to 50 deg. F..   Permanently covering
plants with sheets or blankets for the duration of the winter can be harmful
and  recommended in southern Arizona.  Even if the temperature under the
drape does not warm up enough to "'cook" the plant, it is likely to warm up
enough. to cause the plant to break dormancy, begin actively growing, and
thus become more susceptible to frost damage. Many of the frost cloths
available may be left on for extended periods without risk of harming the
plant."




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