The San Francisco call., 1896-04-26
Valuable Suggestions and Data in
the United States Weather
Bureau.
WATER USED AS A PREVENTIVE
Advice as to the Best Locations in
Which to Plant Fruits and
Other Crops.

In view of the fact that the climate of
California has varied somewhat from the
normal in the beginning of the present
year, discussion has arisen among agri-
culturlsts and business men as to the pros
poets for the fruit, grain and wine crops
this year.
On the subject of the condition and prob
able outcome of the fruit crop very reliable
and extensive data have been gathered
and are on file at the Weather Bureau in
this City. From these data many inter
esting facts may be collated. For instance,
the month of February OF the present year
is distinguished as being the warmest of
any ever recorded in this State. The first
three days in March were signallzed by
heavy frosts, which caused great disaster
throughout the State.
While the temperature of February aver
aged five degrees Fahrenheit above the
| normal, April is averaging five degrees
below the normal, and within the past
week four frosts have occurred throughout
the State, which will undoubtedly prove
disastrous to the crops, the favorable en-
vlronments for an early harvest having
been obliterated by the low temperatures
following the February warm spell.
The State seems to have taken a wrong
stand with reference to the storm center,
and instead of the usual April heat there
have been cold showers from the north
west, with hailstorms and local frosts
| But the reports of damage by frosts in
March were, generally speaking, exaggera-
tIons, and there is reason to suppose that
while the weather of April will greatly
diminish productiveness, fruit, by reason
OF its limited quantity, will command a
higher price than when plentiful. The
result OF the frosts upon the navel oranges
will illustrate this idea. Early in the sea-
son estimates of the crop varied from
| 5000 to 10000 carloads, but the total ship
| ment reached only 5437. Now, while the
loss of several thousand carloads was occa-
stoned by frosts, the orange crop this sea-
son brought better price than t1did dur
ing the past five years. At the present
time advice given by W. II. Harmon,
forecast official of the Weather Bureau,
who has the welfare of the agriculturists
OF California especially in mind, will
prove of value. He gives information as
to the best locations where orchards or
gardens will be the least liable to Jury by
frosts. He directs to avoid as far as pos
sible placing the tenderest plants on low
ground, especially on the bottoms of mar
| row valleys with high hills on both sides.
In addition to the loss of their own heat
| by radiation these valleys will become
filled on frosty nights with the air which
has been cooled by the rapid radiation on
the slopes and has then flowed downward
into the bottoms. Bottom lands opposite
| the mouths of canyons should be espe-
cially avoided for the same reason.
The converse of this is true that plants
on gentle slopes are less liable to injury
than bottom lands. Slopes facing the
south are preferable to northern slopes,
because they receive the rays of the sun
more directly and for longer period dur
ing the day. Slopes facing the west are to
! be preferred to those with an eastern ex-
posure, since they receive heat longer in
the afternoon, and being shaded for time
in the morning from the direct rays of the
sun the slower disappearance of the frost
| seems to cause 1t to be less injurious. The
| fact that frosted plants are more seriously
| injured by being suddenly warmed in the
dry air than when the frost disappears
| gradually seems we'll established
Localities that can be easily flooded for
the purpose OF protection are to be pre-
| ferred to dry sections of otherwise similar
| location, for the evaporation of the moist
ure OF the soil on dry, cold nights will tend
| to raise the dew point of the air, and this
diminishes the probability of frost.
| The irrigation of the hillsides about
valley in which protection is desired and
the growing thereon of plants or trees
with large quantity of foliage will by
the evaporation from the soil and verdure
| tend to raise the dew point of the surface
! air as it flows downward into the valley.
| When the dew point is thus raised to 80
degrees the probability of frost is annulled.
| In places where irrigation can be prac-
| ticed it will be found of great value as
preventive. Let the water be turned on
until the ground in thoroughly mostened.
| The evaporation of the water from the
damp soil will tend to raise the dew point.
Since evaporation takes place near the
| surface tins method is especially valuable
/ In protecting low plants and shrubs, and
| has also been found very valuable in pro-
| tecting citrus groves from freezing weather.
| The irrlgating should be done at as early
an hour as possible, preferably on the day
! preceding the night when frost is ex-
| pected, and the ground kept thoroughly
wet until all danger is passed. A modi-
| fed form of protection which is valuable
! in orchards is to spray the trees with
water. This plan is probably more ,valu-
able than the other in projecting citrus
and other plants which are not injured
until the temperature has fallen several
degrees below the freezing point, for in
these cases the water will tend to freeze
before the fruit is injured, and in freezing
will make sensible large quantity of heat,
thus preventing further cooling OF the air
For the method to be successful the spray
ing must be continued until the tempera-
ture rises.