FROST 
haps four to eight years of age it will 
take two or three times as many pots as 
in an old orchard with spreading limbs 
almost touching each other and effective- 
ly trapping the heat. A perfect knowl- 
edge of the frost possibilities of any par- 
ticular tract will guide one as to the 
amount of protection necessary. It would 
be safe to say that from 150 to 200 pots 
will be needed in very young orchards 
situated in what are known as “cold 
spots.” Every orchardist knows, or 
should know, where these spots are. 
When wood is the fuel to be used it 
should be secured early, and must be 
dry. Most of the firing done by wood 
has been with old rails which were well 
seasoned and burned without difficulty. 
Cordwood has also been used to a some- 
what less extent, but, nevertheless, with 
entire satisfaction. Wood is very clum- 
sy and much in the way, and there is no 
doubt that its use will be abandoned in 
the near future. Some growers, however, 
are of the opinion that wood is the best 
fuel, and it is quite probable that for 
small tracts its use will be continued. 
There is really no difficulty in handling 
it if properly placed, but for large tracts 
I would rather think its use to be quite 
out of the question. The element of 
time consumed in placing it as well as 
the space it takes up in the orchard, 
thus interfering with cultivation, argues 
against its use. The number of wood 
fires necessary for large trees may be 
all the way from 25 to 50. The fires 
should not be large, since large fires tend 
to produce convective air currents and 
may be more harmful to the orchard as 
a whole than the same number of small 
fires. In most orchards it was found 
that the temperature could be raised six 
to ten degrees. Manure, sawdust and 
rubbish are used mainly to create a 
smudge, and are of practically no value 
in raising the temperature. In using 
wood these materials are often quite an 
additional help in holding the heat gen- 
erated by the burning wood. It often 
happens that the temperature cannot be 
kept above the danger point; if this hap- 
pens toward morning the smudge is ben- 
2— 24 
1025 
eficial in protecting the frozen blossoms 
and fruit from the morning sun, which 
would tend to thaw them too rapidly. It 
is not the freezing of the fruit that 
causes the injury; it is the thawing. 
Blossoms may be frozen solid for sev- 
eral hours and not be injured if thawed 
out very slowly. Freezing causes the 
water to be abstracted from the cell pro- 
toplasm. The protoplasm has taken this 
water up from the soil very slowly. If 
the water which has been abstracted 
from it can be returned very slowly the 
cell will recover its former activities. 
No matter what fuel is to be used a plen- 
tiful supply should be distributed in the 
orchards. Even if fifty pots will do the 
work it is better to have one hundred 
or more for each acre even in an orchard 
of old trees. The same may be said of 
wood. It is only necessary to light as 
many fires as will keep the temperature 
above the danger point. It is as great a 
mistake to light too many fires as it is 
to light too few, for the reason that 
burning unnecessary fuel may cause a 
shortage at a time when lack of fuel 
would mean a total loss. Once the tem- 
perature goes very much below the dan- 
ger point it is hard to raise it, and if 
this happens very near sunrise a smudge 
dense enough to protect the frozen blos- 
soms may be hard to secure or to keep 
hanging over the orchards. It is best 
to take no chances. 
Thermometers and Frost Alarms 
Good thermometers should not be 
overlooked, and no fewer than two or 
three per acre should be used for the 
best results. These instruments should 
not be the very cheap kind, although it 
is not advised that they should be very 
expensive. All thermometers should be 
tested and the correction for the differ- 
ent points on the scale carefully marked 
so as to be easily read. A thermometer 
with its correction is just as good as one 
that reads absolutely true. As a mat- 
ter of fact, the very best thermometers 
are not accurate, and must have correc: 
tions made for different parts of the 
seale. For the orchardist, it is usually 
sufficient to know within at least half a 
