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The craftsman
Vol. XXIII, Number 2 (November 1912)

Methods of frost protection,   p. 237 PDF (526.5 KB)

Page 237

A VERY seasonable bulletin has been
       published on the above subject by the
       Department of Meteorology of the
Agricultural Experiment Station at Cornell
University, and, although it deals primarily
with frosts in New York State, much of the
information is of general interest and ap-
plication. The following extracts may be
of assistance to those who wish to protect
plants and fruit trees from the disastrous
effects of frost:
  "For the farmer who is prepared to make
practical use of a frost warning, the fore-
casts issued by the Weather Bureau should
receive first consideration because they may
be obtained early in the day, before it is pos-
sible to obtain any reliable indications from
local observations as to the probability of
frost. But when the warnings issued by
the Weather Bureau cannot be obtained
and the farmer must rely on himself, there
are no instrumental readings that will take
the place of a careful observation of the
condition of the sky, the direction and force
of the wind, and the trend of temperature.
  The object sought in all methods of frost
protection is to hold the temperature of the
air in contact with the plant above the point
of danger.   In the attempt to accomplish
this certain principles are involved:
   I. Prevention or retardation of the escape
of heat from the earth by the use of an arti-
ficial covering. The use of smudges as a
means of protection against frost is based
on this principle.
  2. Addition to the air of moisture in the
form of vapor, with the view of obtaining
the effect of liberation of latent heat as the
moisture condenses. The use of damp fuel
for smudges and the spraying of fires with
water have this purpose in view.
  3. Heating the air by small fires.
  It is a very old practice to protect plants
from frost by covering them with newspa-
pers, carpets, straw and the like. This is a
most cleanly and efficient method, but un-
fortunately, because of the labor and ex-
pense involved, it is applicable in practice
only to small areas, such as flower beds and
gardens. However, by a small investment
in tarred building paper the practice may be
extended profitably to considerable areas.
When the paper is cut into convenient
lengths and two or three strips are fastened
or pasted together so as to make a strip
eight or ten feet wide, which can be rolled
and unrolled easily, this method may be
used for the protection of a fairly large
area. It affords a very convenient and effi-
cient protection for strawberries, garden
truck or small fruits. Paper of this kind
can be purchased for one or two cents per
square foot, and should last several years.
  Smudging, particularly when damp fuel
is used, combines the first and second prin-
ciples mentioned above-the prevention of
the escape of heat from the ground and the
addition of moisture to the air. In practice
smudging has not proved a very efficient
method of protection. It is used chiefly at
present to shield the blossoms from the sun
during the morning hours following a frost,
thus preventing too rapid thawing. Spray-
ing the frozen fruit or blossoms with water
is practiced, also with the same purpose in
view. It is not so much the freezing that
causes injury, as too rapid thawing. It is
said that blossoms may be frozen solid for
hours without injury if thawed very slowly.
  The most practical, efficient and econom-
ical method yet devised for protection of
large areas is the direct addition of heat by
means of numerous small fires properly dis-
tributed over the area to be protected.
  For the farmer who desires to protect the
farm orchard, this method is offered as nei-
ther difficult nor expensive. However, it
does require foresight and careful prepara-
tion. The fuel to be used must be on the
ground and ready for instant use. More-
over, it must be dry, so that fires mav be
started quickly when the temperature ap-
proaches the point of danger. A small in-
vestment in an alarm thermometer will ob-
viate the inconvenience of remaining up at
night to watch for the time when the fires
must be started. These thermometers are
constructed to ring an alarm bell when the
temperature approaches the danger point.
The alarm thermometer should be located
in the coldest part of the orchard and set to
ring the bell when the temperature is still a
few degrees above the point of danger, so
as to give time to get the fires started.
  Wood, coal and oil are the fuels in use,.
and the choice must depend on local price
and supply.

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