Almonds are grown in nearly every county in California. In some counties
the few trees growing only occasionally succeed in producing a crop of
nuts. There are sections in nearly all parts of the state, however,
where they are a success commercially. Within these sections may be
found desirable and undesirable locations, depending upon soil and
moisture conditions and freedom from injurious frosts. Any discussion of
a district, therefore, does not necessarily mean that all lands within
that district are uniformly adapted to almond culture. On this account
it is impossible to define a district any more closely than to name the
center and include with it the outlying districts. In the same way it is
sometimes impossible to say just where one district begins and another
ends. Adaptability of any special location can be determined only by
careful study of the land itself and diligent inquiry of those familiar
with it.
As far as possible, districts should be chosen where a definite cold
winter season exists. Warm weather and lack of freezing temperatures do
not hold the trees fully dormant and any frequent occurrence or unusual
continuation of spring weather in the winter will start the trees into
growth; cooler weather following, interferes with the normal flow of sap,
results in injury to the tree and blossoms, and often causes gumming
of the nuts which mature. This condition exists largely in the lower
elevations in Southern California and especially in the coastal portion,
where the ameliorating influence of the Pacific is felt. This same
condition exists close to the coast in the northern portion of the state.
Further inland and at higher elevations the winters are more pronounced,
and where these are not too severe or prolonged the almond thrives best.