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Copyright 2005, Board of Trustees, University
WATERMELON AND GRAPE INVESTIGATIONS LABORATORY .
Mimeo Report WGL64-1 January 31, 1964
GRAPE GROWERS' QUESTIONS AND ANSWERS
L. H. Stover, J. A. Mortensen, end ..C. Adlerz
The following is a compilation of answers to questions that
have been asked frequently by grape growers. Recently in Florida,
grapes have been grown mostly by home gardeners. The questions
that follow primarily reflect their need for basic information in
grape culture. The answers are intended to provide brief, but
detailed information on the varieties that are available and the
best known methods and procedures for growing them successfully.
1. Can bunch grapes be grown in Florida?
Answer: Lake Emerald (light green) and Blue Lake (blue)
were developed for adaptability to a warm, humid climate and
are long-lived and productive in most areas in Florida.
2. Can Lake Emerald and Blue Lake be marketed?
Answer: Lake Emerald and Blue Lake are essentially home
garden grapes. Both have been sold to a limited extent in
local trade but are not recommended for planting for the
table grape market.
3. Should Lake Emerald and Blue Lake be grafted on a rootstock?
Answer: Lake Emerald is satisfactory without grafting on any
other rootstock. It is vigorous, productive, and long-lived
in nearly all well-drained soils and is frequently used as a
rootstock for other selections.
Blue Lake is sometimes improved by grafting on Lake Emerald
but is usually recommended for growing on its own root system.
4. Do Lake Emerald and Blue Lake require pollen from other grapes
or will they bear fruit in isolated plantings?
Answer: These varieties are both self-fertile (receiving
pollen from their own flower structure) and either variety
will fruit well growing alone.
5. Will California .grapes (Thompson Seedless, Emperor, Ribier
etc.) succeed in Florida on a rootstock such as Lake Emerald?
Answer: No. These grapes are not adapted to this area and
cannot be made so even by the use of a well-adapted rootstock.
6. Will the well-known northern varieties (Concord, Niagara,
Fredonia) live and produce satisfactorily when grafted?
Answer: Usually not. Some of the varieties have been grown
for a few years with intensive care, but basically they- are
not well adapted to this area.
7. Is there any likelihood of better bunch grape varieties being
introduced that will thrive under Florida conditions?
Answer: The Watermelon and Grape Investigations Laboratory
has an active breeding program from which new improved varieties
should be developed from time to time.
8. Can a prospective grower do anything to prepare for new grape
Answer: Since Lake Emerald is suitable for use as a rootstock
in Florida, a small planting of this variety might serve as
the source of wood for rapid rootstock increase and thus shorten
the time necessary to bring any newly-released variety into
full fruit production.
9. Can I get dependable results by growing grapes from seeds?
Answer: No. Grapes do not come true from seed.
10. What method of propagation is recommended for grapes?
Answer: Rooted grape, nursery stock customarily is produced
from cuttings made in December and January from 9- or 10-month
-old wood. Canes used for hardwood cuttings should be about
12 inches long, with 2 or more buds, pencil-diameter or a
little larger, healthy, fairly strhilght, and mature. The
bottom cut should be just below the lowest bud and the top
cut about 1 inch above another bud. The cuttings should be
tied tightly in bundles of 50 or less with the bottom ends
A cool, shady location should be chosen for the callusing
bed. A trench should be dug slightly deeper than the length
of the cuttings. The bundles should be placed in an inverted
position (node-cut ends up) in the trench and soil pulled
around them and packed firmly. Additional soil should be used
to provide about 3 inches of cover over the entire bed. Gut-
tings placed in a bed of this type in a cool shady location
will callus and start roots in about 6 weeks.
A moist location or at least one where watering can be done
should be chosen for the nursery. Nursery rows should be 4
or 5 feet apart and callused or rooted cuttings should be
lined out about 10 inches apart in the row. Bonemeal scat-
tered thinly in the planting furrow prior to setting the
cuttings promotes better root development on the young plants
Cuttings must be set right side up in the nursery row,
They should be set with almost their entire length covered
with soil and kept moist until they are growing rapidly, Such
cuttings will be ready for digging the following winter.
11. What is the recommended procedure for grafting grapes?
Answer: Some grape varieties are frequently more productive
when grafted on a rootstock. Although several methods of
grafting or budding are possible, the cleft graft on .1-year-
old rootstocks, made either in the nursery or in the field,
Grafting in central Florida should be done preferably about
February 1. The rootstock should be cut off with a saw or
sharp shears at a smooth place between nodes about 2 inches
above ground level. The stump, if small, should be split
with a sharp knife; larger stumps may be split with a grafting
tool or chisel.
The budwood for scions should be chosen from the healthiest,
medium-diameter cuttings available. A graft scion should be
5 to 8 inches long and have 2 or more buds. The portion of
the scion to be inserted in the cleft should be cut carefully
to a long, tapering wedge, preferably slightly thicker on 1
side. The wedge cut .should be started close below the basal
bud on both sides. The scion should be inserted carefully
and pushed down well into the cleft so that the cambium on
its thicker edge and that of the stump coincide. The pres-
sure of a large stump may hold a scion securely; small stumps
should be tied firmly with raffia or soft string that will
rot away after a few weeks.
Mounding grafts with soil is the method still most commonly
used. The graft should be banked with clean, moist soil up
to the top bud of the scion. Grafts must not be allowed to
dry out. During dry periods watering will be necessary about
twice a week. A small depression made in the top of each
mound will facilitate watering. The grafted vine should be
trained on a stout permanent stake.
12. Are soil types and locations important for grapes in Florida?
Answer: The promising areas for grapes have a wide range of
soils including most of the soils suited to citrus culture,
Fine sahds and upland soils, especially those with underlying
clay at about 3 feet, are ideal for grapes,
Soils less adapted to viticulture are the white sands, e.g.
St. Lucie, Leon, and St. Johns. Immokalee fine sand has been
used by bedding and controlling moisture. Hard red clay, any
poorly drained soils, marl, peat, muck, and peaty mu-:i are
Growers may well avoid planting grapes in pockets having
poor air drainage, for late spring frosts may des'rL,,j lender
shoots and bloom.
13. Should land for grapes be prepared ahead of time?
Answers Yes, when possible. The preparaticnal requirements
of sites for grapes vary. Frequently a sumne'r covsr crop of
hairy indigo is desirable to increase the organic content of
the soil. Rye may be planted in the early winter and turned
under before grapevines are set. Dolomite at 2 ton to l ton
per ecre may be desirable on new land, if calcium and magnesium
are limiting and soil is more acid than pH 5.$.
14. In what direction should rows be laid out?
Answer: North to south when possible so that both sides of
the vine will get sunlight at some time during the diy'
15. What spacings between rows and between plants in the row are
Answer: The following spacings with the accompanying vines
per acre are most commonly used:
Between plants Plants
rows in row per acre
10' x 10' 435
10' x 9' l48
10' x 8' 540
10' x 6' 720
16, At what time in the year should grape nursery vines be
transplanted to the vineyard rows?
Answer: Transplanting in late dormancy is recommended.
South Florida, January
Central Florida, February
North Florida, March
17, How should a grapevine be planted?
Answer: Similarly to many other perennials. Set the young
plant at the same depth that it was growing in the nursery,
18i Should compost or other fertilizers be used when the vine
Answer: Use only steamed bonemeal around the roots when
planting a grapevine. This is important. Amroniation and
heating from mixed fertilizers, poultry compost, or other
organic fertilizers are frequently severe and may kill vines.
Wait until the young plant is growing rapidly before applying
19, Should a trellis be in place before the vineyard is planted?
Answer: This is optional. If a stout stake about 6 feet
long is placed at each plant shortly after planting, the
erection of trellis may be deferred until mid-summer, thus
20, What type of trellis is recommended for Florida bunch grape
Answer: The simplest and least expensive trellis for grapes
in Florida consists of one No. 9 or No. 10 wire placed on top
or on the side of treated posts at a height of $ feet from
ground level. Space posts to accommodate 3 or 4 plants between
posts. End posts should be braced in a manner to carry the
heavy trellis load.
21. How are young plants trained the first year?
Answer: A stout stake (11 x 11 inches, or larger) should
be placed at each vine soon after planting, regardless of the
type of trellis constructed at planting or later. The stakes
should be sharpened and driven into the ground 5 inches from
the young vine and deep enough to stand alone and support a
young growing grapevine. This stake should be wired permanent-
ly to the main or top wire of the trellis.
At break of dormancy, new shoots emerge rapidly from the
-et plants' top buds. Select the healthiest and secure it
to the guide stake with tyig..; raffia. Thus the main shoot
will become the trunk of the vine. As it grows upward,
continue to tie with raffia, for commerical raffia rarely cuts
or strangles enlarging wood. Train the trunk straight by
tying often. When the trunk shoot reaches the main wire of
the trellis, it should be cut off so that lateral shoots will
be forced to grow along the trellis in both directions establ-
ishing a framework for fruit production.
22, When is dormant pruning done?
Answer: The approximate periods for dormant pruning in
'T.o-rida are as follows:
a. South Florida January
b. Central Florida January 15 to February 15.
c. North Florida February 1 to March 10.
23 What type of wood is designated by the term "fruit wood" or
"fruit canes" and how is a vine pruned to utilize it?
Answer: The terms "fruit wood" or "fruit canes" denote grape-
vine runners that at dormancy (mid-winter) are most promising
for fruit production the following season. Lake Emerald and
Blue Lake are pruned similarly. Mature plants should be
pruned to a bearing framework of 3 or 4 (8- to 12-bud) canes
of new wood with a total of 30 to 50 buds, depending on the
agetaj d .-vigor of the vine. Three or four 3-bud spurs may be
left for the renewal of fruiting canes. These renewal spurs
should be located as close to the main trunk as possible in
order that non-productive old wood between the fruiting wood
and main trunk can be kept at a minimum.
24! What will happen if vines are not pruned at all?
Answer: The number of clusters will increase but the size
of both clusters and berries will decrease to the point that
only stems and cull berries are produced.
2~, Wild vines grow luxuriantly in trees or in the shade of trees,
Can I follow this plan with good results?
Answer: Only with wild vines. Lake Emerald and Blue Lake
must have full sunlight to make healthy, vigorous growth and
produce fruit. These varieties should be planted in a sunlit
area away from competition with trees and shrubs.
26. What kind of fertilizer should be used on grapes? How much
and at what intervals?
Answer: Usually ready-mixed commercial fertilizers analyzing
6-6-6 or 4-8-8 will supply sufficient plant food. A 6-6-6
fertilizer mixture with about 30 percent of the nitrogen
derived from natural organic sources will be satisfactory for
most central Florida locations. The rates of application
should vary with the age of the vines. The small quantity of
steamed bonemeal applied directly on the roots at planting
time should be supplemented the first year with mixed fertilizer
in 3 applications of 1 pound each in eerly March, May, and
Lake Emerald and Blue Lake vines in their second year
should receive 3 applications of about 1 pound each of the
Three applications per vine totalling 4 pounds of mixed
fertilizer should bQ used in the third year and annually
thereafter under most conditions.
Fertilizer should be scattered thinly and evenly, at least
12 inches from young vines and farther from vines at later
applications, since roots attain length rapidly. To get best
results from fertilizer, clean cultivation is advisable un-il
27. Should grapevines be sprayed? If so, when and with what?
Answer: A spray program for grapes in Florida is advisable
to minimize fruit losses. Spraying should begin in the
spring when buds are about 2 inches long and EEl@eoihue at
intervals of 10 days to 2 weeks until berries have attained
maximum size. Zineb at 1 pound plus maneb at 3/4 pound per
hundred gallons of water is an effective fungicides for the
control of foliar diseases on grape in Florida. Small lots
of spray may be made by using 2 tablespoons of zineb plus i and
1/2 tablespoons of maneb to 3 gallons of water. Make a
cream or slurry of the zineb and maneb with a small quantity
of water before adding to the partially-filled tank. Add-
ition of a spreader material (e.g. Triton B-1956)is optional.
Malathion emulsifiable concentrate (56%) may be used for
insect control at the rate of 24 liquid ounces to 100 gallons
(1 1/2 tablespoons to 3 gallons). Garden stores carry
ready-mixed materials for disease and insect control.
28. What type of cultivation is required in a grape planting?
Answer: The feeder roots of grapes are located near the
surface. Therefore, shallow cultivation with a disk harrow,
Acme harrow, sweeps, or rotavator is recommended. Hoes and
rakes are satisfactory for cultivation in small arbors.
In young vineyards clean cultivation throughout the year
is recommended. In established vineyards no cultivation is
needed from fruit harvest to December, during which period
a cover crop is desirable. Hairy indigo (Indigofera hirsute
L.) is satisfactory in central Florida, In late fall the
planting should be cleaned up by disking or shallow plowing.
29. What can be done to protect grapes from birds?
Answer: Damage from birds is frequently severe, especially
on small plantings. If few vines are involved, individual
screening of vines or bagging of clusters may be effective.
Home garden growers sometimes devise their own methods of
protection, using baby chick wire on a large permanent
frame over several vines, or making removable panels of 1
inch mesh for seasonal use only. Devices for frightening
birds, unless used on a large commercial scEle, are usually
less effective than screening or covering.