The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1895-03-18
PREVENTING FROST.

The Vacaville region furnishes most of
the earliest fruits that reach the market.
This year a great part of the crop has been
destroyed by an early frost. In those parts
of the State where fruit is less forward the
damage has been slight As the frost was
general the injury is measurable by the
extent to which poisoning had proceeded.
a chart showing the areas affected, to-
gether with the extent of the damage in
each, would be a safe and valuable guide to
prospective orchardists.
We are made to realize pointedly that
although the profits of early deciduous
fruits are much larger than those of fruits
grown in more backward localities therisk
of producing them is greater. 1t becomes,
then, important to inquire whether it is
possible to eliminate the danger of frost
in the forward localities. The intelligence
and watchfulness of orchardists have
hitherto proved able to overcome all other
enemies that have arisen. The two or
three deadly kinds of scales that few
years ago created profound alarm and
threatened to exterminate the industry
were studied and fought with persistency
that ended in victory. When it was dis
covered that the phylloAera had invaded
certain parts of the State, destroying vine
yards, it was found that budding into
the wild native grapevines of California
and Arizona completely checked the
enemy.
Frost is the next evil to be met and over
come. In Southern California it has been
fought most intelligently in the citrus
orchards since the heavy disaster of few
years ago. 1t is familiar knowledge that
hoar-frost is dew which has frozen by the
falling of the temperature to 80 degrees or
below; that dew does not fall on windy
nights, because there is constant shifting
of air which prevents the precipitation of
the moisture in the atmosphere; nor on
cloudy nights, because the clouds prevent
such a radiation of the earth's heat as will
permit the temperature to fall to the freez-
ing point; and that hoar-frost, or the snow
like form that frozen dew takes on, is quite
different thing from the ''frost" of the
orchardist, which is more properly a
Greece" Thus, the night may be either
windy or cloudy, and yet the fruit may be
frozen and thus destroyed. This is I'M
! common, but possible and it is well that
we keep it in mind.
Then, the three means that can be en-
Ploy GU, as d iulS, W Keep away ITOSb are
the producing of clouds or something to
serve their purpose, the raising of the
temperature and the agitation of the air.
Smudge fires, made of some slow-b burning
substance which produces abundant smoke,
are cheap and efficacious, if set not too far
apart, and especially if there is a slight
movement of air, which there nearly
always is. As the direction of these air
currents is almost invariably constant, it
is easy to ascertain which is the windward
side of the orchard. In Southern Califor-
MIA water sprays are said to be employed
to some extent. The only purpose that
they can serve is to raise the temperature,
as water, in order not to be ice, must be
warmer than 80 deg. The spray may also
produce slight movement of the air, but
this can hardly be regarded as an impor-
tant factor.
The problems involved in handling the
frost problem are very simple, and the
subject is one deserving of study. The
amount which Vacayille has lost in a sim
gle season would have been sufficient, if
invested in frost-preventing means, to in
sure protection for many years.