PROPAGATION
The grape commends itself to commercial and amateur growers alike by
its ease of propagation. The vines of all species may be propagated
from seed, and all but one of the several cultivated species may be
grown readily from cuttings or layers. All yield to grafting of one
kind or another. Seeds are planted only to produce new varieties. At
one time stocks were grown from seed, but this practice has fallen
into disrepute because of the great variations in the seedlings.
Varieties on their own roots and stocks are for most part propagated
from cuttings. In the production of stocks, the viticulturist sets the
orchardist a good example, for there can be no question that all
tree-fruits suffer from being grown on seedling stocks. The grape is a
vigorous, self-assertive plant and once it is started, whether from
seeds, cuttings or layers, seldom fails to grow.
SEEDLINGS
Growing seedling grapes is the simplest of operations. The seeds are
taken from the grapes at harvest time, after which they must pass
through a resting period of a few months. At once or in a month or
two, the seeds should be stratified in moist sand and stored in a cold
place until spring, when they may be sown in flats or in the open
ground; or seed may be sown in a well-prepared piece of garden land in
the autumn. When planted in the open, autumn or spring, the seeds are
put in at the depth of an inch, an inch or two apart and in rows
convenient for cultivation. Subsequent care consists of cultivation
if the seed are sown in garden rows, and in pricking out when true
leaves appear if planted in flats. In ground that crusts, an expedient
is to mix grape seed with apple seed; the apple seedlings, being more
vigorous, break the crust and act as nurse plants to the more tender
grapes. Sometimes it is helpful to the young plants to mulch the
ground lightly with lawn clippings or moss. Grape seedlings grow
rapidly, often making from two to three feet of wood in a season.
The young plants are thinned or set to stand four or five inches apart
in the nursery row. At the end of the first season, all plants are cut
back severely and almost entirely covered with earth by plowing up to
the row on both sides. This earth, of course, is leveled the following
spring. If the seasons are propitious and all goes well, the seedlings
are ready for the vineyard at the end of the second season, but if for
any reason they have fared badly during their first two years, it is
much better to give them a third season in the nursery. Seedling vines
are seldom as vigorous as those from cuttings, and unusual care must
be taken in setting in the vineyard, though the operation is
essentially the same as that to be described for vines from cuttings.
The third season the vines are kept to a single shoot and are pinched
back when the canes reach a length of five or six feet. In the autumn,
they are pruned back to two or three feet. In the spring of the fourth
season, the trellis is put up and a few fruits may be allowed to
ripen.
The vines of promise may now be selected. The plants, however, must
fruit twice or oftener before it can be told whether hopes are
consummated or must be deferred. Growing seedlings for new varieties
is a game full of chances in which, while there may be little
immediate or individual gain, there is much pleasure. It is hardly too
much to say that the grape industry of eastern America, with its
300,000 acres and 1500 varieties, betokens the good that has come from
growing seedling grapes.
DORMANT CUTTINGS
Vines for vineyards, with the exception of varieties of Rotundifolia,
are propagated from cuttings of hard wood taken from the season's
canes when the vines are pruned. The inactive buds in these cuttings
may be brought into active growth, and roots induced to grow from the
cut surfaces by various means. By this miracle of Nature, an infinite
number of plants, in an endless procession, may be propagated from the
product of a single seed, each plant complete in its heredity and
differing from its fellows only in accordance with environment.
_Time to make cuttings._
A good cutting should have a protective callus over the cut and this
requires time, so that the sooner cuttings are made after the wood
becomes thoroughly dormant the better. Besides, the cutting should use
its stored food material for the formation of adventitious roots
rather than have it pass into buds, as it quickly does late in the
dormant season when buds are about to open. If cuttings must be made
late in the season, transplanting must be delayed as long as possible,
and the cuttings be set in a northerly aspect to prevent the premature
development of the buds. However, the grape responds surprisingly well
to the call of Nature in forming roots, and great importance need not
be attached to the time at which the cuttings are made.
_Selecting cutting wood._
Cuttings are made from one-year-old wood; that is, canes produced
during the summer are taken for cuttings in the fall. Immature canes
and those with soft, spongy wood ought not to be used. Strong vigorous
canes should be given preference over weak growth, but most nurserymen
maintain that very large canes do not make as good cuttings as do
those of medium size, the objection to large size being that the
cuttings do not root as well. Short-jointed wood is better than
long-jointed. Cuttings from vines weakened by insects and fungi are
liable to be weak, soft, immature and poorly stored with food. The
wood should be smooth and straight.
_Making the cutting._
Grape cuttings vary in length from four inches to two feet, the length
depending on the climate and the soil of the nursery and the species
and variety. The hotter and drier the climate and the lighter the
soil, the longer the cutting needs to be. Six to nine inches, however,
is the usual length in the climate of eastern America, while on the
Pacific slope the length varies from eight to fifteen inches. For
convenience in handling, all cuttings should be approximately of the
same length, to insure which some kind of simple gauge is needed.
Various gauges are used, as marks cut in the working table, a stick of
the required length, or a cutting-box.
In making the cuttings, a slanting cut is made close below the lowest
bud, while about an inch of wood is left above the upper bud. When
possible, a heel of old wood is left at the lower end; or, still
better, a whorl of buds, as roots usually start from each bud. The
finished cuttings are tied in bundles, all butts one way, and are then
ready to be heeled-in. This is done by burying in trenches, butts up,
and covering with a few inches of soil. It is important to invert the
cuttings in trenching, since otherwise the tops often start to grow
before the butts are properly calloused, and it is very essential that
the tops remain dormant until roots appear to support the new growth.
_Planting the cuttings._
Cuttings are planted in the nursery in rows wide enough apart for
cultivation and two or three inches apart in the row. Trenches are
made with a plow; perpendicular if the cuttings are shorter, and a
little slanting if longer than six inches. The cuttings are set at a
depth which permits the upper buds to project above the ground, as
shown in Fig. 6. When the cuttings in a row are placed, two inches of
soil are put in and pressed firmly about the base of the cuttings.
Then the trench is evenly filled with earth and the cultivator
follows. Doing duty by the young plants consists in cultivating often
during the summer to keep the soil moist and mellow.
[Illustration: FIG. 6. Planting cuttings.]
The cuttings are planted as soon as the ground is warm and dry enough
to work. To delay planting too long invites injury from drought, which
almost annually parches the land in eastern America. Irrigation gives
more leeway to planting time in the West. When warm sunny weather,
accompanied by an occasional shower, predominates, the cuttings start
growth almost at once, as shown in Fig. 7, and by fall, all things
being propitious, make a growth from four to six feet. With the
cuttings three inches and the rows three feet apart, 58,080 vines may
be grown to the acre.
[Illustration: FIG. 7. A cutting beginning growth.]
_Single-eye cuttings._
New and rare varieties are propagated from single-eye cuttings,
thereby doubling the number of plants from the propagating wood. This
method gives an opportunity, also, to start the work of propagating
early in the season, since single-eye cuttings are nearly always
rooted by artificial heat. But the greatest value of the method is
that some varieties which cannot be propagated in any other way
readily grow under artificial heat from single-eyes. Well-grown vines
so propagated are as good as those grown by any other method, but the
great disadvantage is that unless much care and skill are used, vines
from these cuttings are poor and quite worthless. It is also a more
expensive method than growing from long cuttings out of doors.
There are several ways of making single-eye cuttings. The most common
form of the cutting is the single bud with an inch of wood above and
below, the ends being cut with a slant. Some modify this form by
cutting away the wood on the side opposite the bud, exposing the pith
the whole length of the cutting. In another form, a square cut is made
directly under the bud, leaving an inch and a half of wood above. Or
this last form is modified by making a long sloping cut from the bud
to the upper end, thereby exposing the maximum amount of cambium.
Advantages are claimed for each form, but these are mostly imaginary,
and the cutting may be made to suit the fancy of the propagator if a
few essentials are observed.
Single-eye cuttings are made in the fall and are stored in sand until
late winter, about February in New York. At this time the cuttings are
planted horizontally an inch deep in a sand propagating bench in a
cool greenhouse. If the cuttings are not well calloused, they remain
one or two weeks in a temperature of 40 deg. to 50 deg. without bottom heat,
but well-made cuttings are calloused and ready to strike root so that
brisk bottom heat can be applied at once. After six weeks or two
months, the young plants are ready to pot off or to transplant in a
cold-frame or cool greenhouse. If but a few plants are to be grown,
they may be started in two- or three-inch pots, shifting into larger
pots once or twice as growth progresses. In early summer, the young
plants are set in nursery rows out of doors and by fall the young
vines should be strong and vigorous.
Single-eyes are also started in hot-beds, cold-frames and even in the
open air without the aid of artificial heat. In hot-beds and
cold-frames, the method is only a modification of that described for
greenhouses. Out of doors the cuttings are given the same conditions
under which long cuttings are rooted, except that the whole of the
short cutting is buried an inch deep in the nursery row.
HERBACEOUS CUTTINGS
Grapes are easily propagated from herbaceous cuttings, although since
the vines are weak and the method expensive, they are seldom used.
Green cuttings are usually taken from plants forced in greenhouses,
but may be taken in summer from vineyard vines. A green cutting is
usually cut with two buds with the leaf at the upper one left on. The
cuttings are set in propagating beds of sand, or pots of sand, in
close frames under which there is brisk bottom heat. To prevent
excessive evaporation, the frames are kept closed and the atmosphere
warm and moist. As growth progresses, or if mildew appears, the frames
are more and more ventilated. In two to four weeks, the cuttings
should have rooted sufficiently well to be transplanted to pots.
Herbaceous cuttings made in the summer must be kept under glass until
the following spring.
LAYERING
The grape is readily propagated from layers of either green or mature
wood, the method being certain, convenient and producing extra
vigorous plants. The drawback is that fewer plants can be obtained by
layering than from cuttings with a given amount of wood. Varieties of
some species, however, cannot be propagated by cuttings, and with
these layering becomes of supreme importance to the propagator. Nearly
all varieties of Rotundifolia and some of AEstivalis are best grown
from layers. So far as is known, all varieties of cultivated species
may be grown by layering, and since the method is simple and certain
and the vines vigorous and easily handled, this method is commended to
small growers of grapes.
_Dormant wood layering._
The work of layering mature wood usually begins in the spring, but the
vines from which the layers are to be taken should have received
preliminary treatment the preceding season. The vines to be layered
are severely cut back a year or more before the layering is to be done
to induce a vigorous growth of canes. Strong vigorous canes are laid
in a shallow trench, two to five inches deep, in which they are
fastened with wood or wire pegs or staples. The trench is then partly
filled with fine, moist, mellow earth which is firmly packed about the
cane. Roots strike and shoots spring from each joint. When the young
plants are well above ground, the trench is completely filled, and
then, or a little later, the young plants are staked to keep them out
of the way of the cultivator. The following fall the young vines are
ready to transplant.
The essentials of layering have been given, but a number of
non-essentials may be helpful under some conditions. Thus, dormant
wood may be layered in the fall, in which case the cane is usually
notched or ringed at the joint to induce the formation of roots. The
less the number of joints covered, the stronger the young vines, so
that while the number is usually five, six or more extra vigorous
plants may be obtained by covering only one or two joints. In
propagating Rotundifolia grapes, it is expected that lateral branches
will make the tops of the new plants. These, at the time of layering,
are cut back to eight or ten inches, all on the same side of the
vine, and are not left closer together than twelve inches. In nursery
practice, Rotundifolia vines are trained along the ground for
layering. Vines on arbors, in greenhouses, or on sides of buildings
are easily layered in boxes or pots of soil. Plants grown from layers
are not as conveniently handled as those from cuttings.
_Green wood layering._
Layered plants from green wood are sometimes grown to multiply quickly
new or rare varieties. The work is accomplished in midsummer by
bending down and covering shoots of the present season's growth.
Strong plants are seldom obtained from summer-layering and it is never
safe to attempt to grow more than one or two plants from a shoot. The
most forceful culture possible must be given summer-layered plants
after the separation from the parent vine. It is very generally agreed
that plants from summer-layers not only do not give good plants, but
that the parent vine is injured in taking an offspring from it in this
way.
_Layering to fill vacancies in the vineyard._
There is sure to be an occasional gap even in the best vineyard. Young
plants set in vacancies must compete with neighboring full-grown
vines, and often in a bit of land so unfavorable that it may have been
the cause of the demise of the original occupant. Under these
circumstances, the newcomer stands a poor chance for life. A plant
introduced by layering a strong cane from a near-by vine has little
difficulty in establishing itself on its own roots, after which it can
be separated from the parent. Such layering is best done by taking in
early spring a strong, unpruned cane from an adjoining plant in the
same row and covering an end joint six inches deep in the vacant
place, but leaving sufficient wood on the end of the cane to turn up
perpendicularly out of the soil. This free end becomes the new plant
and by the following fall or spring may be separated from its parent.
Not infrequently the young plant bears fruit the second season on its
own roots. This method is of especial value in small plantations,
whereby the trouble of ordering one or two plants is avoided and the
advantage of early fruiting is obtained.
GRAFTING
Since grafting grapes is intimately connected with stocks, the growing
of which is a modern practice, grafting is thought of as a new process
in growing this fruit. Quite to the contrary, it is an old practice.
Cato, the sturdy old Roman grape-grower who lived nearly two hundred
years before Christ, speaks of grafting grapes, although Theophrastus,
the Greek philosopher, wrote a hundred years before "the vine cannot
be grafted upon itself." However, until it became necessary to grow
Vinifera grapes on resistant stocks to avoid the ravages of
phylloxera, grafting the grape was not at all common among
vineyardists and is not now except where vines susceptible to
phylloxera must be grown in consort with roots resistant to this
insect, or to modify the vigor of the top by a stock more vigorous or
less vigorous. For these two purposes, grafting is now in some grape
regions one of the most important vineyard operations.
In grafting the grape, there is a time and a way, not so particular as
many believe, but rather more particular than in grafting most other
fruits. If the essentials of grafting are kept in mind, one has
considerable choice of details. Grafting consists in detaching and
inserting one or several buds of a mother plant on another plant of
the same or a similar kind; the bud stock is the cion, the rooted
plant is the stock. The essentials may be set forth in three
statements: First, the prime essential is that the cambium layers, the
healing tissue lying between the bark and wood, meet in the cion and
stock; second, that method of grafting is best in which the cut
tissues heal most rapidly and most completely; third, the greater the
amount of cambium contact, as compared with the whole cut surface, the
more rapidly and completely the wounds will heal. Out of a great many,
the following are a few of the simplest methods in use in grafting the
grape, any one of which may be modified more or less as occasion
calls.
_Vineyard grafting in eastern America._
[Illustration: FIG. 8. Cutting off the trunk.]
In eastern America, the growing vine is usually grafted. At the New
York Agricultural Experiment Station, the operation is very
successfully performed on old vines as follows: Preparatory to
grafting, the earth is removed from around the stock to a depth of two
or three inches. The vines are then decapitated at the surface of the
ground and at right angles with the axis of the stock. If the grain is
straight, the cleft can be made by splitting with a chisel, but more
often it will have to be done with a thin-bladed saw through the
center of the stock for at least two inches. The cion is cut with two
buds, the wedge being started at the lower bud. The cleft in the stock
is then opened, and the cion inserted so that the cambium of stock and
cion are in intimate contact. If the stock is large, two cions are
used. The several operations in grafting are shown in Figs. 8, 9, 10
and 11. Grafting wax is unnecessary, in fact is often worse than
useless, and if the stock is large the graft is not even tied. Raffia
is used to tie the graft in young vines. It suffices to mound the
graft to the top of the cion with earth, for the purposes of
protection and to keep the graft moist. Two or three times during the
summer, sprouts coming from the stock or roots from the cion should be
removed.
[Illustration: FIG. 9. Cutting the cleft.]
A method used with fair success at the New York Agricultural
Experiment Station with young vines is to plant one-year-old stocks in
the nursery row as soon as the ground can be worked in the spring.
Just as the vines start in growth, these are cut off at the surface of
the ground and whip- or cleft-grafted with a two-eye cion. The graft
is tied with raffia, after which it is all but covered with a mound of
soil. This is a case in which the work must be done at the accepted
time, as it is fatal to delay.
[Illustration: FIG. 10. Inserting the cion.]
[Illustration: FIG. 11. The completed graft.]
R. D. Anthony describes another method as follows:[2] "A method which
a Pennsylvania grower of Viniferas has found very satisfactory is to
root the Vinifera cuttings, and grow them one year on their own roots;
then the vine which is to be used as a stock is planted in the
vineyard and the rooted cutting planted beside it so that the shoots
from the two may be brought in contact with each other. In June when
the plants are in full growth, two vigorous shoots (one from each
vine) are brought together and a cut two or three inches long made in
each parallel to the length of the cane removing from one-third to
one-half of the thickness of the shoot. These flat surfaces exposed
by the cuts are then brought into contact with the cambium tissues
touching and are tied in place. The tops are checked somewhat by
breaking off some of the growth. The following spring the Vinifera
roots are cut off below the graft and the top of the stock above the
graft is removed."
In the subsequent care of these young vines, the grower must take time
by the forelock and tie the grafts to suitable stakes; otherwise they
are liable to be broken off at the union by wind or careless workmen.
Grafted vineyards must have extra good care in all cultural
operations, and even with the best of care from 5 to 50 per cent of
the grafts will fail or grow so poorly as to make regrafting
necessary, this being the most unfavorable circumstance of field
grafting. Regrafting is done one joint lower than the first operation
to avoid dead wood; this brings the union below the surface of the
ground, and the vineyardist must expect many cion roots to try his
patience.
_Vineyard grafting on the Pacific slope._
Vineyard grafting, according to Bioletti,[3] was formerly the
commonest method of starting resistant vineyards in California. After
stating that it is best whenever possible to plant good cuttings
rather than roots, and that the grafting should usually be done the
year after planting, Bioletti gives the following directions for
grafting:[4]
"Wherever possible the vines should be grafted at or above the surface
of the ground. In many cases, however, it will be necessary to go
below the surface to find a smooth, suitable part of the stock where
grafting is possible.
"The kind of graft to use will depend on the size of the stock. For
stocks up to 2/3 inch in diameter the methods of tongue and wire
grafting already described are the best. For larger vines up to 3/4
inch a modification of the ordinary tongue graft is the best. If the
tongue graft were made in the usual way with stocks of this size, it
would be necessary to use excessively large scions, which is
undesirable, or to have the barks unite only on one side. By cutting
the bevel of the stock only part way through the vines, it is possible
to make a smaller scion unite on both sides. For still larger vines,
those over 3/4 inch in diameter, the best graft is the ordinary cleft.
"No wax or clay should be used on the graft. Anything which completely
excludes the air prevents the knitting of the tissues. A little clay,
cloth, or a leaf may be placed over the split in the stock when the
cleft graft is used, simply to keep out the soil. Otherwise there is
nothing more suitable or more favorable to the formation of a good
union that can be put around the graft than loose, moist soil. If the
soil is clayey, stiff or lumpy, it is necessary to surround the union
with loose soil or sand brought from outside the vineyard.
"It will usually be necessary to tie the grafts. A well-made cleft
graft often holds the scion with sufficient force to prevent its
displacement and no tying is necessary. Wherever there is any danger
of the graft moving, however, it should be tied. There is nothing
better for this purpose than ordinary raffia. The raffia should not be
bluestoned, as it will last long enough without and will be sure to
rot in a few weeks, and the trouble of cutting it will be avoided.
Cotton string or anything which will keep the graft in place for a few
weeks may also be used.
"As soon as the graft is made and tied, a stake should be driven and
the union covered with a little earth. The hilling up of the graft may
be left for a few hours, except in very hot, dry weather. Finally, the
whole graft should be covered with a broad hill of loose soil 2 inches
above the top of the scion.
"Field grafting should not be commenced as a rule, except in the
hottest and driest localities, before the middle of March. Before
that there is too much danger that heavy rains may keep the soil
soaked for several weeks--a condition very unfavorable to the
formation of good unions. In any case the grafting should not be done
while the soil is wet. Grafting may continue as long as the cuttings
can be kept dormant. It is difficult to graft successfully, however,
when the bark of the stock becomes loose, as it does soon after the
middle of April in most localities."
As in the East, it is necessary in California to remove suckers from
the roots and roots from the cions once or twice during the summer.
Suckers should not be allowed to overshade the graft, though it is
best not to remove them until danger of disturbing the graft is past.
The grafts should be staked and the vines looked after as recommended
for eastern conditions.
[Illustration: PLATE III.--Cover-crops. _Top_, cow-horn turnips;
_bottom_, rye.]
_Bench grafting._
The resistant vineyards of France and California are now started
almost entirely with bench-grafted vines. It has been learned in these
regions that a grafted vine, to be a permanent success, must have the
consorting parts perfectly united, and that the sooner the grafting is
done in the life of stock and cion the better the union. Cions of the
variety wanted are, therefore, grafted on resistant roots or resistant
cuttings in the workshop and then planted in the nursery. Bench
grafting has the advantage over field grafting in time gained and in
securing a fuller stand of vines.
Bench grafting really begins with the selection of cuttings, since
success largely depends on good cuttings of both stock and cion.
Cuttings are taken from strong healthy vines and are of medium size,
with short to medium joints. The best size is one-third of an inch in
diameter, that of stock and cion being the same since the two must
match exactly. The cutting-wood may be taken from the mother vines at
any time during the dormant season up to two weeks before buds swell
in the spring, and the cuttings can then be made as convenience
dictates, though meanwhile the wood must be kept cool and moist, which
is best done by covering them with moist but not wet soil or sand in a
cellar or cool shed. In California, the best results are obtained when
the grafting is done in February or March, though it may be begun
earlier and continued a month later.
_Preparation of cuttings._
The stocks are cut into lengths of about ten inches, a gauge being
used to secure uniform length. The cut at the bottom is made through a
bud in such a way as to leave the diaphragm. The top cut is made as
near ten inches from the bottom as possible, leaving about one and
one-half inches above the top bud for convenience in grafting. The
stock is then disbudded, taking both visible and adventitious buds,
the latter indicated by woody enlargements, to keep down the number of
suckers.
[Illustration: FIG. 12. Bench-grafted cuttings of grape, showing both
the cleft-graft and the whip-graft.]
The cion should be made with but one bud, thereby gaining the
advantage of having every cion the same length so that all unions are
at the same distance below the surface of the ground in the nursery.
The cion is made with about two and one-half inches of internode below
the bud and one-half inch above, a sharp knife being the best tool for
making the cuts.
Stock and cion cuttings are now graded to exactly the same diameters,
this being necessary to secure perfection in the unions. Three
methods of uniting stock and cion are illustrated in Fig. 12. It
suffices to grade by the eye into three lots--large, small and
medium--but some nurserymen prefer to secure even greater accuracy by
the use of any one of several mechanical gauges. The methods of
uniting stock and cion may be described best by quoting Bioletti, from
whom most of the details already given have been summarized:[5]
_Tongue grafting._
"When the stocks and scions are prepared and graded the grafter takes
a box of stocks and a box of the corresponding size of scions and
unites them. Each is cut at the same angle in such a way that when
placed together the cut surface of one exactly fits and covers the
whole of the cut surface of the other. The length of cut surface
should be from three to four times the diameter of the cutting, the
shorter cut for the larger sizes and the longer for the thinner. This
will correspond to an angle of from 14.5 to 19.5 degrees. The cut
should be made with a sliding movement of the knife. This will make
the cut more easily and more smoothly.
"The cut should be made with a single quick motion of the knife. If
the first cut is not satisfactory, a completely new one should be
made. There should be no paring of the cut, as this will make an
irregular or wavy surface and prevent the cuttings coming together
closely in all parts.
"The tongues are made with a slow, sliding motion of the knife. They
are commenced slightly above one-third of the distance from the sharp
end of the bevel and cut down until the tongue is just a trifle more
than one-third the length of the cut surface. The tongue should be
_cut_, not _split_. The knife should not follow the grain of the wood,
but should be slanted in such a way that the tongue will be about
one-half as thick as it would be if made by splitting. Before
withdrawing the knife it is bent over in order to open out the
tongue. This very much facilitates the placing together of stock and
scion.
"The stock and scion are now placed together and, if everything has
been done properly, there will be no cut surface visible and the
extremity of neither stock nor scion will project over the cut surface
of the other. It is much better that the points should not quite reach
the bottom of the cut surface than that they should overlap, as the
union will be more complete and the scions will be less liable to
throw out roots. If the points do overlap, the overlapping portion
should be cut off, as in the Champin grafts.
"A skillful grafter, by following the above-described method, will
make grafts most of which will hold together very firmly. Many of them
would be displaced, however, in subsequent operations, so that it is
necessary to tie them. This is done with raffia or waxed string. The
only object of the tying is to keep the stock and scion together until
they unite by the growth of their own tissues, so that the less
material used the better, provided this object is attained. For the
formation of healing tissue air is necessary, so that clay, wax,
tinfoil or anything that would exclude the air should not be used. The
tying material is passed twice around the point of the scion to hold
it down firmly, and then with one or two wide spirals it is carried to
the point of the stock, which is fastened firmly with two more turns
and the end of the string passed under the last turn. The less string
is used the more easily it is removed later in the nursery.
"Untreated raffia should be used for late grafts which are to be
planted directly out in the nursery, but if the grafts are to be
placed first in a callusing bed it is best to bluestone the raffia in
order to prevent rotting before the grafts are planted. This is done
by steeping the bundles of raffia in a three per cent solution of
bluestone for a few hours and then hanging them up to dry. Before
using, the raffia should be washed quickly in a stream of water in
order to remove the bluestone which has crystallized on the outside
and which might corrode the graft.
"Some grafters prefer waxed string for grafting. The string should be
strong enough to hold the graft, but thin enough to be broken by hand.
No. 18 knitting cotton is a good size. It is waxed by soaking the
balls in melted grafting wax for several hours. The string will absorb
the wax, and may then be placed on one side until needed. A good wax
for this purpose is made by melting together one part of tallow, two
parts of beeswax, and three parts of rosin."
_Wire grafting._
"The merits claimed for this method are that it is more rapid,
requires less skill, and does away with the troublesome tying and
still more troublesome removal of the tying material. Practiced
grafters can obtain as large a percentage of No. 1 unions by this
method as by any other, and unpracticed grafters can do almost as well
as practiced. Another advantage of the method is that the scions have
less tendency to make roots than with the tongue graft.
"It consists essentially of the use of a short piece of galvanized
iron wire inserted in the pith of stock and scion for the purpose of
holding them together, thus replacing both tongues and raffia. It has
been objected that the iron would have a deleterious effect on the
tissues of the graft, corroding them, or causing them to decay. There
seems, however, no reason to expect any such result, and vines grafted
in this way have been bearing for years without showing any such
effect.
"The preparation and grading of stocks and scions are exactly the same
for this method as for the tongue graft.
"Stock and scion are cut at an angle of 45 degrees. A piece of
galvanized iron wire two inches long is then pushed one inch into the
firmest pith. This will usually be the pith of the stock, but it will
depend on the varieties being grafted. The scion is then pushed on to
the wire and pressed down until it is in contact with the stock. If
the cuttings have large pith it is better to use two pieces of wire,
one placed in the stock first and the other in the scion.
"The length of wire to use will vary with the size and firmness of the
cuttings, but 2 inches will usually be found most satisfactory. Wire
of No. 17 gauge is the most useful size."
_Making bundles._
"If the grafts are to be planted out directly in the nursery, they may
be simply laid in boxes or trays, covered with damp sacks, and carried
out to be planted as soon as made. It is usually better, however, to
place them for several weeks in a callusing bed before planting. In
this case it is necessary for convenience of handling to tie them up
into bundles. No more than twenty grafts should be placed in a bundle,
and ten is better. If the bundles are too large there is danger of the
grafts in the middle becoming moldy or dry.
"A stand is very convenient. It consists of a piece of board 12
inches, on one end of which is nailed a cleat 6 inches by 4 inches and
under the other end a support of the same size. Two 4-inch wire nails
are driven through the board from below, 4 inches apart and 5 inches
from the cleat. Two other 4-inch nails are driven similarly at 1-1/2
inches from the other end. The grafts are laid on this stand with the
scions resting against the cleat, and are then tied with the two
pieces of bluestoned raffia that have previously been placed above
each pair of nails. This arrangement insures all the scions, and
therefore the unions, being at the same level, and puts both ties
below the union where they will not strain the graft. The tying is
more expeditious and less liable to disturb the unions than if the
bundles are made without a guide.
"A skillful grafter will make about one hundred tongue grafts on
cuttings per hour, or from sixty-five to seventy-five per hour if he
does the tying as well. Wire grafts can be made at the rate of two
hundred and fifty or more per hour, and by proper division of labor
where several grafters are employed this number can be easily
exceeded. These estimates do not include the preparation and grading
of the cuttings."
_Grafting rooted cuttings._
The cion may be grafted on a stock rooted in the nursery the previous
season, much the same methods being used as with cuttings. This method
is employed to utilize cuttings too small to graft, the added sizes
attained in the nursery making them large enough, and in grafting on
stocks which root with difficulty, thus saving the making of grafts
which never grow. The stocks, in this method, are cut so that the
cions may be inserted as the original cutting and not as the new
growth. The roots, for convenience in handling, are cut back to an
inch or thereabouts in length.
_The callusing bed._
If bench grafts are planted at once in the nursery, most of them fail.
They are, therefore, stratified in a callusing bed where moisture and
temperature can be controlled. Bioletti describes a callusing bed and
its use as follows:[6]
"This callusing bed is usually a pile of clean sand placed on the
south side of a wall or building and surrounded by a board partition
where there is no possibility of its becoming too wet by the flow of
water from a higher level or from an overhanging roof. It should be
protected, if necessary, by a surrounding ditch. It should be
furnished with a removable cover of canvas or boards to protect it
from rain and to enable the temperature to be controlled by the
admission or exclusion of the sun's rays. A water-proof wagon-cover,
black on one side and white on the other, is excellent for this
purpose.
"The bottom of the callusing bed is first covered with 2 or 3 inches
of sand. The bundles of grafts are then placed in a row along one end
of the bed, and sand well filled in around them. The bundles should be
placed in a slightly inclined position with the scions uppermost, and
the sand should be dry enough so that it sifts in between the grafts
in the bundle. The bundles of grafts are then covered up completely
with sand, leaving it at least 2 inches deep above the top of the
scion. Another row is then placed in the same manner until the bed is
full. Finally a layer of 2 or 3 inches of moss or straw is placed over
all.
"In the callusing bed we should endeavor to hasten and perfect the
union of stock and scion as much as possible while delaying the
starting of the buds and the emission of the roots. The latter
processes require more moisture than the formation of healing tissue,
therefore the sand should be kept comparatively dry. Between 5 and 10
per cent of water in the sand is sufficient. The purer the sand the
less water is necessary. There should be a little more moisture
present than in the sand used for keeping the cuttings over winter.
Too much moisture will stimulate the emission of roots and starting of
buds without aiding the callus formation.
"All the vital processes progress more rapidly when the cuttings are
kept warm. To delay them, therefore, we keep the sand cool, and to
hasten them we make it warm. In the beginning of the season and up to
the middle of March we keep the sand cool. This is done by keeping the
bed covered during the day when the sun is shining, and uncovering
occasionally at night when there is no fear of rain. If the
black-and-white wagon-cover is used, the white side should be placed
outward to reflect the heat. The temperature should be kept about 60 deg.
F. or lower.
"About the middle of March the temperature of the bed should be
raised. This is done by removing the cover during warm days and
carefully covering at night. If necessary the layer of moss or straw
should be removed on sunny days and then replaced. The temperature of
the sand at the level of the unions should be about 75 deg. F. during this
period. If the temperature rises higher than this, there will be a
more abundant production of callus, but it will be soft, easily
injured, and liable to decay.
"At the end of four weeks after warming the bed, the union should be
well cemented. The callus should not only have formed copiously around
the whole circumference of the wound, but it should have acquired a
certain amount of toughness due to the formation of fibrous tissue. It
should require a pull of several pounds to break the callus and
separate stock and scion. When the callus has acquired this quality
the grafts are in condition to be planted in the nursery, and may be
handled without danger. If taken from the bed while the callus is
still soft, many unions will be injured and the grafts will fail, or
unite only on one side.
"If left as long as this in the callusing bed most of the scion buds
will have started and formed white shoots. These shoots, however,
should not be more than 1/2 to 1 inch long. If they are longer the bed
has been kept too wet or too warm. Roots will also have started from
the stock, but these also should not be over 1/2 inch long. The grafts
should be handled as carefully as is practicable, but there is no
objection to breaking off any scion shoots or stock roots which have
grown too long. It is almost impossible to save them, and new ones
will start after the grafts are planted, and make a perfectly
satisfactory growth."
_Care in the nursery._
The grafts are planted in the nursery, and are given much the same
care recommended for cuttings. They may be set in trenches made with
plow or spade; or they may be planted in very shallow trenches with a
dibble. After planting, the grafts are covered with an inch or two of
soil, thus forming a wide ridge in the nursery row with the union of
the grafts at the original level of the soil. Cultivation should begin
at once and be frequent enough to prevent the formation of a crust, in
order that the young shoots may not have difficulty in forcing their
way through the soil. Roots start on the cions sooner than on the
stock, the soil being warmer at the surface, and help sustain the
cions until the stocks are well rooted, at which time all roots
started on the cion are removed, and at the same time the tying
material is cut if it has not rotted. Suckers are removed as soon as
they show above ground. The grafts are dug as soon as the leaves fall
and the young vines become dormant, after which they are sorted in
three lots, according to size of top and root, and heeled-in in a cool
moist place until they are to be planted.
_Nursery_ versus _home-grown vines._
The verdict of all vineyardists is that it is better to buy
nursery-grown vines than to attempt to grow them. The high quality of
the vines which can be purchased and the reasonable purchase price
make it hardly worth while to try home-grown vines, especially since
considerable investment, experience and skill are required to grow
good vines.
"PEDIGREED" GRAPE VINES
Many viticulturists, in common with orchardists, believe that their
plants should be propagated only from parents which have good
characters, that is, are vigorous, healthy, productive, and bear fruit
of large size, perfect form, good color and good quality. They
believe, in short, that varieties can be improved by bud selection.
There is, however, but little in either theory or fact to
substantiate the belief of those who say that varieties once
established can be improved; or, on the other hand, that they
degenerate. Present knowledge and experience indicate that heredity is
all but complete in varieties propagated from parts of plants. The
multitude of grapes in any variety, all from one seed, are
morphologically one individual. A few kinds of grapes go back to
Christ's time, and these seem to agree almost perfectly with the
descriptions of them made by Roman writers 2000 years ago. How, then,
can the differences between vines of a variety in every vineyard in
the land be explained?
Ample explanation is found in "nurture" to account for the variation
in vines without involving a change in "Nature." Soil, sunlight,
moisture, insects, disease, plant-food, and the stock in the case of
grafted vines, give every vine a distinct environment and hence a
distinct individuality of its own. Peculiarities in a vine appear and
disappear with the individual. A variety can be changed temporarily by
its environment, but remove the incidental forces and it snaps back
into its same old self.
Heredity is not quite complete in the grape, however; for, now and
then, sports or mutations appear which are permanent and, if
sufficiently different, become a strain of the parent variety or
possibly a new variety. There are several such sports of the Concord
under cultivation. The grape-grower can tell these sports from the
modifications brought about by environment only by propagation. If a
variation is transmitted unchanged through successive generations of
the grape, as occasionally happens, it may be looked on as a new form.
"Pedigreed" vines, then, should be subject to a test of several
generations in an experimental vineyard before the grape-grower pays
the price demanded for the supposed improvement.
[Illustration: PLATE IV.--A well-tilled vineyard of Concords.]