Pullman herald. [volume] (Pullman, W.T. [Wash.]) 1888-1989, 1912-11-08


may or may not be soaked with oil
The number of pots per acre depends
upon local conditions and the severity
of the frost Many growers use a pot
Tor each tree, while some use more.
The average number of pots used for
apples and pears is about eighty per
acre. The number of heaters required
for an old orchard is less than for a
young one. This is que to the fact that
the young trees are small and do not
arrest as much heat as do larger trees.
The cost OF equipping an orchard with
these little heaters ranges from twenty
to sixty dollars per acre, depending
upon the type and number of pots used.
The annual cost of operating the pots
ranges from five to twenty dollars per
acre. When one considers the value
of the fruit crops that are saved it IS
easily seen that the heaters are a pay
ing investment.
1t Is an important phase of frost
fighting to know the dangerous
periods in the life of the young fruit.
1t is popular opinion that the danger
point at all times and with all kinds of
fruit is 30 degrees Fahrenheit, or the
point at which water freeves This,
however, is a great mistake, as the
danger point will vary greatly, depend
ing upon the stages of development of
the buds, flowers, or fruit. In the tests
made by the Missouri Agricultural Elk
pertinent Station it was found that in
the life of the peach bud there are four
stages at which the crop may be lost
from cold injury The first stage is
that of the fully dormant buds as we
find them in winter. At this time,
under normal conditions, they can
stand eight or nine degrees below
zero. The second stage is from the
time growth in the buds begins until
they are fully open. At this time the
killing temperature is zero. This is u
critical period, as severe weather is apt
to appear at this time The third stage
is the time that mtervenes between the
opening of the buds and the time the
petals foil The danger point at this
time is from 26 to 30 degrees above
zero. The fourth and last stage begins
after the fruit has set and lasts until
all danger of cold weather is passed
just after the young fruit has been
formed and at the time when the calyX
is beginning to fall, the young fruits
can stand a temperature of 30 degrees.
Beyond this stage the larger the
peaches are the less cold they can with
stand. The government makes the fol
lowing statement as to danger points.
Apples showing pink 20 degrees, in full
bloom 26 degrees. Pears showing pink
20 degrees in full bloom 27 degrees.
1t is not advisable to allow the tenn
perature to fall so low as stated above.
for under certain conditions the buds
would be destroyed at such tempera-
lures.
When the thermometer says that the
time for fighting has arrived no time
should be lost. 1t is essential to have
a force of men that are industrious,
careful and observing to the last de-
gree. In lighting the heaters not more
than Is or 80 per cent should be light
ed at first, for usually the temperature
drops slowly, and by watching a mum
Der Of thermometers throughout the Or
chard the temperature in the orchard
may be controlled at any desired de-
gree. A good system of lighting is to
light every second pot in every. other
row. This is sufficient for two to four
degrees rise in temperature. 1t is
mistaken idea held by some growers
that it is best to raise the temperature
in an orchard by the amount of heat
produced by each heater already light
ed The government, in all its reports
sounds a warning in this regard and
brings out the point very strongly that
there is no need for great heat locally,
but for small fires well distributed.