How to Propagate Grapes from Cuttings by Lon Rombough

We are propagating several heirloom grapes this year: Deleware, Vincent, Campbell Early, Salem, Isabella, Agawam, Eaton, Green Mountain, Lindley, Barry, Brighton, Perkins, and Wilder.  In boning up on the process–we have only dabbled in grapes heretofore–I came on an excellent article by Lon Rombough.  I liked the piece so much, I sent a request for permission to reprint it.  Lon’s wife, Susan, wrote back with the news that Lon had passed away a couple of years ago, giving us permission to reprint the piece in Lon’s honor.  For more about Lon and his work, check out the links below: 

  • Grapes, writing, consulting, book, The Grape Grower, at http://www.bunchgrapes.com  Winner  GWA “Best Talent in Writing”  2003.

~  ~  ~

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.

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.  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%
hydrogen peroxide 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
To store cuttings, wrap them in moist paper or pack them in material
such as damp peat, in a plastic bag. Keep cuttings refrigerated or stored 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 it can dry them. The ideal temperature is 32-33o F (0-1oC). Properly stored, cuttings can be held for as long 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 first 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.  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 bare root 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 85 F (25 C), 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 perlitepeat
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 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 desiccation. 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.

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. 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.

On-Site Rooting of Cuttings
This is a shortcut method of rooting grape cuttings that several people
have tried with enough success to make it worth posting here. Cuttings
are rooted right in the place where the vines are to grow.

Note 1. Time of year. This method is done after all danger of frost is past
and the weather is consistently warm.

Note 2. Site preparation. Till the soil at the site where the vines are to
grow and clean off weeds.

1. Step one. For each vine, put down a sheet of clear plastic mulch, 2
feet (1.25 Meter) by 2 feet (1.25 Meter) and secure the edges either by
burying them. This is done a week before planting. Or use a continuous
strip if you are planting a row.

2. After a week, prepare the cuttings with an application of Dip ‘N’ Grow
rooting hormone, diluted to the strength listed for “easy to root” plants.

3. Push the cuttings through the plastic film at least half way into the
soil.

4. Within one to four weeks the cuttings should root and begin to push
buds. It may take longer if the weather is cool. When shoots are at least
six inches tall, the vines can be watered and fertilized with something
mild like fish fertilizer, and then again on a regular basis after that.

5. Train the shoots as they grow and with good care the vine should
grow at least enough to produce a trunk by the end of the season. The
plastic may be removed once the vines are at least a foot tall, and organic
mulch put down in place of it. If you leave the plastic, be sure to remove
it by the end of the season.

In this method, the clear plastic allows sunlight through to the soil,where
its energy is converted to heat. The plastic traps the heat,warming the
soil enough to help the cuttings form callus and roots. If the cuttings are
planted where the mature vines are to be located, the new shoots can be
trained up a support stake as they grow, so that the new vine may get big
enough to bear a small crop the next season. The success of this method
will vary with climate, soil, and grape variety.

Sources:
Mycorrhizal Fungi Sources: T and J Enterprises
http://www.tandjenterprises.com/cgibin/
ustorekeeper.pl?rtn=gsjb121000
Bio-Organics
http://www.bio-organics.com
Heat Mat
Grow For It
http://www.bird-x.com/products-groforit-gromats-c-5_17.html
Phone: 1-800-662-5021
This heat mat is well suited to grape cuttings because it is set to a higher
temperature and the amount of heat can be varied by how close the
flat/pot is to the mat.
Rooting Hormone
Dip’N’ Grow – available in garden stores, or contact:
Astoria-Pacific, Inc.
Clackamas, OR 97015-0830
Phone: 1-800-536-3111
Fax: 503-655-7367
ZipSet Pots – very nice system of paper pots and collapsable flats for
rooting cuttings in combinations with the heat mat from GrowForIt. Pots
can be left on the cuttings when planted. 2 x 2 x 6 inch pots work well
with cuttings. These pots are available from:
http://monarchmfg.com/
The Monarch Company 800 284-0390 or email
monarch@monarchmfg.com

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