_Sulphuring._--Sulphuring the vines is now considered a most necessary
operation, and without doing it well and in time no good crops can be
relied upon. It is true that good crops of grapes are sometimes had
without sulphuring, but this is only due to chance; the absence of
mildew, and immunity from disease of unsulphured vines are rare, even in
otherwise most perfectly kept vineyards.
The sulphuring consists in thoroughly dusting the growing vines, leaves,
branches, flower buds and berries with powdered sulphur. The first
sulphuring must be done when the grapevines leaf out in the spring, and,
when the young shoots are about six inches long, it is about time to
commence. Many growers sulphur only once, some go over their vines two
times, but our most successful growers,--those who get the best and
largest fruit crop of grapes and bunches,--sulphur in unfavorable
seasons three or four times. The second sulphuring is done just before
the blossoms open, and may even, provided the weather remains cool and
windy, be done in the open blossoms with great benefit to the setting
berries. Miss M. F. Austin of Fresno was the first to successfully
sulphur in the open blossom, the result being very large crops. But not
all have been as successful as she, and one of our most experienced
vineyardists and raisin-growers, T. C. White, prefers to sulphur just
before the blossom opens, as, in case of very warm weather when the
sulphur is thrown on the blossom, the latter is apt to blast. We are
therefore on the safe side if we sulphur just before the buds have
opened, and after the grapes have set. But on cold, windy days when one
of the cold electric northwest winds are sweeping down the valleys,
sulphuring must be done whether the blossom is open or not, as it is
just at this time the sulphur is required the most, in order to
counteract the formation of the first stage of the powdery mildew. The
vapor of the sulphur destroys the germs of the mildew, and thus prevents
the latter from causing the grapes to fall off. After the grapes have
fully set, no further sulphuring is required except in the case of heavy
rains or in continued cloudy weather, when there is always danger that
the mildew will reappear. If heavy rains should occur during the summer,
a renewed sulphuring is always necessary or at least advisable, but in
ordinary seasons no sulphuring is needed after the berries have set
well, as the germs of the mildew are then sufficiently injured to not
develop later in the season.
Sufficient sulphuring is always noticeable in the vineyard by its smell,
and, when this smell is strong and pronounced, no further sulphuring is
required. The sulphur is applied to the vines either by the “dredger”
(or dust-can) or by a pair of sulphur bellows. The dredger is used when
the vines are small, while the bellows are necessary to spread the
sulphur evenly when the vines have reached a certain size. Many growers
use, during the first sulphuring, small burlap bags filled with sulphur.
The meshes of the burlaps are large enough to allow the sulphur to go
through. The sulphur should be finely pulverized to be effective, and
the sublimated French sulphur is by many considered the best. The cost
of sulphuring varies according to the size of the vines, but is
generally about three dollars per acre. Young vines under three years of
age require little sulphuring, while older vines require a great deal.
About ten tons of sulphur will be enough for 160 acres.
_Tying Over._--The tying over of the branches is another vineyard
operation much used in the interior raisin districts, generally in the
end of June or the middle of July. It consists in so bending and tying
the long, straggling branches of the vine that they will shade the
grapes hanging in the center. The long branch is bent, not in a direct
line towards the center, as it would then expose too many of the lower
grape bunches, but in a spiral direction round the vine. If there is any
fear that the grapes will be exposed and sunburned, and the vines have
not been properly summer pruned, the tying over is the only process by
which great loss can be prevented and the grape crop saved. In tying
over, no twine is used. The end of the long branch is twisted and
fastened to other branches, and, when the grapes are ripe and the
picking season comes, a single light pull will suffice to untie all and
allow the grapes to be picked. Great care should be used in tying over,
lest the lower branches become exposed and sunburned. Careless or
inexperienced laborers will often accomplish a great deal of work and a
great deal of harm in an incredibly short time. I have seen vineyards
where more harm was done by tying over than by the sun and wind
combined.
_Covering the Vines._--Instead of tying over, many vineyardists now
cover the vines, and place the covers on the open center of the vine, in
order that they may protect the grapes from exposure to the sun. This is
done in June, several days before the hot spell is expected. The last
week in June is the best time almost everywhere in California, as the
vines are then open in the center, and any unusually hot weather would
easily cause the grapes to sunburn. The process of covering is very
simple. With a pair of shears the longest branches are clipped off and
immediately placed on the open center. This is generally enough to
prevent the exposed grapes in the center of the vine from being scalded.
More than half a dozen branches will seldom be required, and at picking
time these dry branches must first be thrown off, so as to give the
picker access to the grapes. The covering of the vines is a better
process than tying over, requiring less work and being more quickly
performed. It is especially useful for old vines, as the grapes of young
vines are principally exposed from the sides.
_Thinning the Crop._--The proper thinning of the crop should be done by
pruning. If the proper amount of wood is left, no thinning out of the
grapes is needed. If a few show-grapes or extra large raisins are needed
for exhibiting purposes, they can be produced by a judicious cutting of
the majority of the grapes from any single bunch. If the free half of
the bunch is cut off, the part that is left will produce very large
grapes. This operation is, however, never likely to enter as a regular
vineyard operation in our vineyards, as with us labor is too scarce. The
object of our raisin industry is to produce cheap medium-sized raisins
of good quality, to be used by the masses of the people, instead of a
smaller quantity of very large grapes, which could only be used by the
rich.
_Ringing the Vines._--This consists in removing a part of the bark all
around a cane. In France and Greece a special instrument is made to
perform this operation quickly and carefully. A ring of bark half an
inch wide is all that is required to have the desired effect. The vines
are ringed when the grapes are half grown, and only a few canes are
ringed on each vine. The effect of ringing is to greatly increase the
crop of grapes, also to produce the grapes earlier in the season. So far
this process has not been used in California to any extent. In the
Grecian Islands, where currants are raised, this ringing has been
practiced for years, with more or less beneficial effect. The sap in the
cane that is ringed is prevented from again returning to the root, and
goes to produce a larger quantity of grapes above the ring. But thereby
the cane is seriously injured, and often to such an extent that it must
be entirely removed the following season. Care must therefore be taken
to leave enough unringed branches to serve as fruit-bearing wood the
following year. If done with care and good judgment, the ringing does no
great injury to the vine. For a fuller account of the process, see
article on Currants.
_The Vineyard Labors of the Year._--The following synopsis of the
various labors in a raisin vineyard can only be of interest to the
beginner, or to any one who contemplates engaging in the raisin
business. The data given are only approximate, as they must differ in
different localities, or according to the changing of the seasons:
_December._--After the first frost, or when the vines are dormant,
planting new vines and cuttings may begin. Pruning the old wood. Burning
the prunings. Manuring the soil.
_January._--Plowing, cultivating and planting.
_February._--Cultivating and plowing.
_March._--Grafting the grapes and finishing plowing.
_April._--Hoeing the vines and cultivating. Sulphuring and suckering.
_May._--Sulphuring and summer pruning.
_June._--Hoeing. Covering or tying over the vines.
_July._--Irrigating where needed. Fixing trays and sweatboxes.
_August._--Distributing trays and sweatboxes in the vineyard. Picking
the first crop. Packing should begin as soon as possible.
_September._--Picking, drying, turning the trays, reversing, taking up.
_October._--Picking the last of the second crop. Packing continues.
_November._--Hauling in, stacking and cleaning off trays and sweatboxes.
Irrigating and manuring the land. New land should be prepared for
planting, which should begin as soon as the first frost has killed the
leaves of the vine.