Freeze Alert!
January 11, 2007
Temperatures early Saturday and Sunday mornings are likely to drop
below those we experienced in 1998, the last time we had a major freeze 'event'
in Northern California. Lows in the upper teens and low 20's can cause serious
damage to citrus trees and other subtropicals.
Plant protection tips--
Cover plants: lightweight spun plastic fabrics usually sold as
"floating row covers," can simply be draped over the plant, as they
are light enough that there won't be damage from contacting the foliage. If you
use any material that isn't clear, you need to remove it during daylight hours.
Plants can't live without light! Wrapping the trunk with burlap can help
prevent major damage in a severe freeze.
Move plants: pull potted plants up against a south or east wall,
under an overhang. Reflected or retained heat from warm walls or cement walks
will provide additional protection. Protect from cold wind. Fences or walls
will prevent additional stress from cold winter winds. If practical, pull the
container into your garage for the next few days.
Water: make sure all plants, especially those in containers, are
well watered. If dry soil freezes,
it will pull moisture from the roots, causing them damage, and we haven't had
measurable rainfall since Dec. 29. If the soil is moist it can freeze without
harming tree roots.
Spray with an antitranspirant. Cloud Cover or Wilt-Pruf
applied just prior to cold weather will give the foliage 3 - 4 degrees
protection against the cold as well as desiccating winds.
Provide a heat source: Christmas lights hung in citrus trees have
proved very successful, even with temperatures in the teens. Landscape lighting
and portable shop lights will work
as well. Make sure the light
source is plugged into a grounded extension cord approved for outdoor use.
Harvest fruit: thin-skinned varieties of citrus could be damaged,
especially those on the outer part of the tree (unprotected by foliage). You
may wish to harvest mandarins, lemons (especially Meyer), and limes, as they
are ripe now and will deteriorate quickly if damaged. Freeze the juice for
later use. Thicker-skinned types
such as navel oranges will probably be adequately protected by covering the
trees, but they are also ripe and could be harvested. Avoid harvesting Valencia
oranges, grapefruits, and tangelos, as they don't ripen until later in the
spring. Fruit does not ripen further off the tree.
Cold as it is, this will not likely break the record for
temperatures set in 1990, when we had 13 consecutive mornings below freezing,
with low temperatures on Dec. 22 and 23 of 18 and 17 degrees.
© 2008 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616
www.redwoodbarn.com
Feel free to copy and distribute this article with attribution to this author.
Click here for Don's other Davis Enterprise articles
