Growing Grapes From Cuttings
Grapes are very easy to grow from
cuttings. With proper care, a dormant cutting can be started
in the spring and by fall will give a vine large enough to
bear a cluster or two of fruit the next season. The important
factors are proper care and preparation of the cuttings.
Grapes can be grown from two types of
cuttings, dormant or hardwood, and green cuttings. Dormant
cuttings are the easiest to handle, but green cuttings work in
situations when it isn't possible to use hardwood, such as for
grapes that don't root easily from dormant cuttings, or when
green cuttings are all that are available.
Dormant Cuttings
Dormant cuttings can be taken any time
after the vine has lost it's leaves until the buds begin to
swell in the spring. Cuttings are made from the new shoots
(canes) that grew the growing season that just ended. The best
wood is the first one to two feet of the base of the shoot
where the buds are closest together, but any healthy, well
matured section of the cane will suffice. Ideal thickness is
pencil diameter up to about 3/4 inch thick.
Thicker cuttings can be hard to handle
and thinner wood may not be mature, though thinner wood may be
acceptable if the variety has naturally small shoots. Avoid
wood that is soft and spongy and has a large pith. Best wood
is dense and light green inside with relatively small pith.
(See Fig. 2) Cuttings should be 12 to 18 inches long, with the
bottom cut off straight, right below the bud, and the top cut
diagonally, 
at
least 1/2 inch above the bud to make it easy to identify the
top, insuring that the cutting will be planted right side up (See
Fig. 1).
Fig. 1.
A.
Some growers make the diagonal cut on the
bottom. Either way works. There should be at least 3 buds
(nodes) on the cutting, more if possible, though two bud
cuttings may serve in an emergency (see fig 2).
Fig. 2.
A. B.
Rooting occurs best at the nodes, hence
the advantage in having several nodes per cutting.
If you take your own cuttings, choose
clean, healthy wood with no discolorations from fungus or
other disease, though fungus disease (black rot, downy and
powdery mildew, and anthracnose) will not harm the cuttings if
the wood well matured. Disinfect such cuttings with a 5%
chlorine bleach solution before growing them, to keep disease
from spreading into the Nursery. Try to observe the vine in
bearing to be sure it is healthy - some virus diseases can
reduce crop, allowing the vine to grow more, so it looks big
and vigorous when dormant, but is unfruitful. Vines grown from
cuttings of a virus-infected vine will also have the virus. If
possible, take cuttings after there has been enough cold
weather to kill any poorly ripened wood, to insure getting
mature wood. Bundle the cuttings with plastic twine or
insulated wire that won't rot or corrode and mark them with
plastic or other rot-resistant material. Use metal or plastic
tags with embossed letters or permanent ink that won't wash
off in moist conditions.
Storing Cuttings
When making your own cuttings, wrap them
in moist paper or pack them in material such as damp peat, in
a plastic bag.
Keep cuttings refrigerated or store them
in an unheated building, in the crawl space under the house.
Avoid places where they will freeze. Freezing, per se will not
harm them, but can take water out and dessicate them. The
ideal temperature is 32-33o F (0-1oC). Properly stored,
cuttings can be held for as much as a year or more.
Large quantities of cuttings can also be
stored by burying them in pits of sand (to prevent
waterlogging) on the north side of a building. They are buried
upside down with 6 -18 inches of sand over them, covered with
tarps and boards. As spring arrives, some or most of the sand
is removed so the bottoms of the cuttings warm and callus in
preparation for planting (see callusing).
Callusing
Callus
is the white tissue that forms on cut surfaces of the cutting,
and can also appear in lines along the sides of the cutting.
It is from callus that roots form. (See Fig 3 & 4)
Fig. 3.
A. B.
Callus
may not always be obvious, but it must be there before roots
develop. Once roots start, they grow in cooler conditions than
are needed for callus to form. A grape cutting pushed into
soil will just sit until the soil is warm enough for callus to
form, so it usually only grows a few inches the first year.
But by pre-callusing the cuttings before planting, they can
grow much more than they would otherwise, often enough to
establish the trunk of the vine, if not more.
A callused cutting planted in it's
permanent location, kept weeded, watered, and well fertilized,
can establish it's roots in place as it grows a top and can
often grow enough to allow it to bear a cluster or two the
next season. This has been done in commercial vineyards in
Oregon. Nursery-grown bareroot vines have to grow a year to
re-establish their roots, before being trained up the second
year, and can finally start to bear the third year, a full
year after a cutting planted at the same time.
Before callusing, be sure cuttings
haven't dried in storage. Standing them in an inch or two of
water overnight will let them "refill," improving
rooting.
There are several methods to callus
cuttings, according to your situation. While rooting hormone
isn't absolutely necessary, it can hasten callusing and
increase the number of roots. A very good product for the
purpose is Dip 'N' Grow (see sources) used at medium strength.
Method 1. Small amounts of
cuttings can be callused by wrapping them in moist paper or
sphagnum in a black plastic bag. This is the way your cuttings
arrive, so if they have been stored properly, they are ready
to callus. Put them in a warm area that stays constantly at
80-85oF. The top of a refrigerator is a good place as the
waste heat from the condenser collects there. Callusing should
occur in one to two weeks. Buds may push and produce white
sprouts, but this isn't harmful, though care should be taken
to avoid breakage as the cutting must use energy to grow more
shoots. Plant as soon as the cuttings are callused and roots
start to appear.
Method 2. Plant the cuttings in a
pot of a mix of 3 parts perlite to 1 part peat, by volume. Set
the pot on a heat mat set to 85oF (25oC), in a cool area, or
even outdoors in a protected area. This heats the root zone
and encourages callusing, but the top of the cuttings, being
in cool air, will not push buds as readily. The idea is to get
roots before buds push too much so there is an existing root
system to support the new growth when it appears. Rooting
occurs in one to two weeks in most cases. See sources for a
company that sells heat mats.
Method 3. Plant the cuttings in a
one gallon black pot of the 3:1 perlite-peat mix and set it in
a sunny location where the pot can be warmed by the sun. The
pot should be no larger than one gallon as the warming effect
of the sun will penetrate a larger pot too slowly. Avoid
excess watering as that will cool the mix and slow rooting.
This is a slower method, often taking as much as a month, and
the buds will often start to grow before the roots are formed,
but it works well enough for home use.
Larger quantities of cuttings can be
bundled in lots of 50 - 100 and rooted in the 3:1 perlite peat
mix in benches with bottom heat (heat cables or hot water
pipes) set at 80 - 85oF (25oC) in the root zone. Ideally, beds
should be outdoors or in an unheated, or even refrigerated,
room to retard sprouting of the buds while the cuttings callus
and root, as in method #2. This reduces the likelihood of
shoots that can break off during planting.
Planting Cuttings
Cuttings callus and root in a short
time, so don't start callusing until the planting site is
ready so the cuttings can be planted immediately. Once
cuttings have a ring of callus on the base, or roots are
starting to appear, it's time to plant them.
Cuttings may be planted: 1. directly in
the spot where you plan to grow the vine; 2. in a Nursery row
where you can grow them until fall, then transplant the vine
when it is dormant; 3. in a pot. In the last case, you can
start cuttings early in the year, then transplant them into
their permanent location from the pot as spring advances, or
even grow them in the pot all summer and set them out in the
fall, if fall planting is possible in your area.
If you lack means to keep the young
vines watered in the permanent location, it is better to grow
vines in a Nursery or pot and transplant them as dormant
vines, which are able to take more stress when they are
planted in the permanent location.
Plant cuttings with half or more of
their length in the soil to help protect them from dessication.
In very hot, dry areas the cuttings can be covered with a
mound of loose soil at first. Keep the soil loose and watch
for buds breaking through. When buds start to grow, pull the
soil mound away from them.
If some of the roots or shoots break
during planting, it isn't a disaster, but avoid it if possible
as the cutting must expend energy to grow more. If white
shoots die or rot back a bit, new shoots will start from the
base of the old shoot.
Water an inch or more a week until the
shoots get to six inches long, then start using a weekly
feeding of a balanced organic fertilizer, such as fish (mixed
according to directions) or a liquid chemical fertilizer such
as 16-16-16. Before the shoots are about 6 inches long, the
roots are not developed well enough to get full benefit from
fertilizer. If you use drip irrigation, the fertilizer can be
applied in the water. Stop fertilizing by mid summer and
reduce or stop water soon after that to allow the vine to
harden before frost.
I have used mycorrhizal fungi with my
grapes and find that these types of fungi, which associate
with the roots and help the plant take up nutrients, are a
definite benefit to the plants. They can be applied directly
to the roots or watered in after planting. Applying them to
the roots before planting seems to have the most effect. If
you do use the fungi, stay with a strictly organic fertilizer
as chemical types will inhibit or destroy the fungi. See
sources for more information.
Green (softwood) Cuttings
Green cuttings are used mainly with
grapes that do not root from dormant cuttings, such as
varieties derived from Vitis lincecumii or V. aestivalis (such
as "Norton"), or Muscadine grapes (Muscadinia
rotundifolia), or when dormant cuttings are not available.
Muscadine grapes started from green cuttings have a success
rate of 70 to 80% versus 1 to 2 % from dormant cuttings. Green
cuttings can also be used to multiply a variety quickly, as
noted farther on.
Make green cuttings from any vigorously
growing shoot. Avoid shoots that have stopped growing and are
starting to harden off and turn brown. Take cuttings as early
as possible in the spring to give the young vine extra time to
harden off, unless you can keep the vine in a greenhouse.
Cuttings should be 4 to 6 inches (10 to 15 cm) long, with two
or three leaves. Remove all but the top leaf and cut that one
in half if it is full size, but leave it alone if it is a
young, undersized leaf (See Fig. 5). Cuttings with no leaves
at all very seldom root.
Fig. 5.
A.
Dip the green cutting in rooting hormone
(see sources) and plant in the same 3:1 perlite peat mix used
for dormant cuttings. The ideal place to plant is in mist
bench with a heat cable in the bottom of it to hold
temperatures at 85oF (25oC) in the root zone. Done this way,
the cuttings will usually root in 6-9 days and be ready to pot
up. Keep them under mist or in high humidity for a few days
until the new roots can keep the plant from wilting.
When held in a greenhouse and forced
with extra fertilizer, the new vine can itself provide
material for more cuttings within two or three weeks. With
this system of using each new batch of rooted plants as
sources of more material, a few cuttings can become thousands
in six weeks.
A
simpler alternative is to use a one gallon black plastic pot,
with a clear plastic bag over it, supported by wires (see Fig.
6).
Fig. 6.
This creates a humid chamber that keeps
the cuttings from wilting until they root. If the pot is
warmed by sunlight, rooting is slower since the pot cools at
night and may take three weeks to a month. If the pot is sent
on a heat mat, to keep the heat constant, rooting is faster.
Vines started from green cuttings need
more protection when set in the vineyard and should be
surrounded by a bottomless milk carton or other device to
shade it until it can withstand direct sunlight.
Either way you do it, your new grapes
will give you pleasure for as many years as you want.
