THIRTY QUESTIONS AND ANSWERS FOR GRAPE GROWERS
J. A. Hortensen, W. C. Adlerz and D. L. Hopkins
The following is a compilation of answ".r J4.ti ns that have been
asked frequently by growers. The que isti( ~imaril reflect the need
for basic information in grape M1t.,tF Phe answers are intended to
provide information on the best vAi7?eties ava dle a"d their culture.
1. Can bunch and muscadine gapes V grown in F.ida?
Answer: 'Lake Emerald; (light green), 'Bl~,Ra,-'b lue), and 'Stover'
(golden) were developed for adaptab'll tcit -,qarm, humid climate and
are long-lived, productive bunch gra.d :i-f most areas in Florida. The
French hybrid 'Roucaneuf' (S.V. 12 -3b9) can be grown on 'Dog Ridge'
rootstock if sprayed regularly for control of anthracnose.
Muscadine grapes are well adapted to Florida, but some varieties
perform better than others (varieties with asterisk acceptable for
wine): For central and north Florida 'Southland'*, 'Cowart'*,
'Chief'", 'Jumbo', 'Magoon'*, 'Creek'", 'Thomas', 'Tarheel'* (all dark
colored) 'Fry', 'Higgins', and 'Welder'l (bronze colored) are the best
varieties. For south Florida 'Hunt'-, 'Pride', 'Cowart' 'Magoon'*,
'Magnolia'* and 'Higgins' have shown promise. However, 'Pride' is
very susceptible to Pierce's disease at Leesburg. 'Carlos' at first
appeared to be outstanding but now is declining in vigor and production
from Pierce's disease. Newer varieties 'Noble'~, 'Watergate', 'Sugar-
gate', and "Redgate' have not been adequately evaluated in Florida so
should be tested by growers on a limited scale.
2. Can the bunch and muscadine grapes be marketed?
Answer: Recent marketing tests with 'Stover' indicated good acceptance
by buyers of this variety for fresh fruit use. It also makes a good
neutral wine. 'Blue Lake' is better for juice and jelly than for
fresh fruit eating. 'Lake Emerald' does not keep well enough for
marketing, but may be eaten fresh from the vine or made into jelly
Muscadine grapes are liked as fresh fruit and for making juice, wines,
jellies, pies, sauces, and preserves. Pick-your-own operations with
muscadines have been highly successful in Florida. Mechanical
harvesting by shaking (except for 'Jumbo' and 'Higgins') may be used
in preparation for marketing larger quantities of muscadine grapes
for processing or fresh market.
Leesburg ARC Research Report WG75-5
September 29, 1975
3. Will California grapes ('Thompson Seedless', 'Emperor',
'Ribier', etc.) succeed in Florida on a nematode-resistant rootstock
such as 'Dog Ridge'?
Answer: No. These grapes are not adapted to this area. The use of
a well-adapted rootstock will increase their vigor but not their
4. Will the well-known northern varieties ('Concord', 'Niagara'7
'Delaware', 'Fredonia') live and produce satisfactorily when grafted?
Answer: Usually not. Some of the varieties have been groim for a few
years with intensive care, but basically they are not well adapted to
5. Will Florida viticulture be limited to varieties listed in
number 1, or will new varieties become available?
Answer: The Agricultural Research Center, Leesburg has an active
breeding program from which new, improved grape varieties should be
developed from time to time. 'Lake Emerald': 'Blue Lake' and 'Stover'
were developed at this Research Center. Also varieties and advanced
selections of grapes developed by breeders from other states are
being tested for growing in Florida.
6. How long does it take for grapes to come into production?
Answer: Well-trained vines of recommended varieties with proper
fertilization, irrigation, and spraying should start bearing the
second growing season after planting (light crop), with a full crop
the third growing season. Poorly trained vines with minimum ferti--
lization, irrigation, and spraying may require four to six growing
seasons to come into bearing.
7. Do bunch and muscadine grapes require pollen from other grapes
or will they bear fruit in isolated plantings?
Answer: 'Lake Emerald, 'Blue Lake', 'Stover', and 'Roucaneuf' are
self-fertile (receiving pollen from their own flowers) and will fruit
well growing alone.
Most of the newer varieties of muscadines do not require pollinators.
However 'Higgins', 'Fry', 'Hunt', 'Jumbo', 'Creek; and 'Thomas' (among
others) require a pollinator. Good pollinators are 'Magoon', 'South--
land', 'Cowart', 'Tarheel' and 'Welder'. Bees are recommended to aid
pollination of female muscadine varieties, but they are a deterrent at
harvest time. Use the pollinator vine every third plant in every third
row, or plant every third row solid with the pollinator variety.
8. Can I get dependable results by growing grapes from seeds?
Answer: No. One cannot predict the kind of grape that will grow
9. How can new plants be produced that are like the mother vine?
Answer: Bunch grapes. Rooted grape nursery stock customarily is
produced from cuttings made in January from 9- or 10o-month-old wood.
Canes used for hardwood cuttings should be about 12 inches long, with
3 or more buds, pencil-diameter or a little larger, fairly straight,
with brown bark and green wood. The bottom cut should be just below
the lowest bud and the top cut 1 inch above another bud. The cuttings
,should be tied tightly in bundles of 50 or less with the bottom ends
even. 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 in the trench,
the soil pulled around them and packed firmly. Additional soil should
be used to provide about 4 inches of cover over the entire bed. The
area should be thoroughly sprinkled with water when top two inches of
soil cover become dry. Cuttings placed in a bed of this type 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 to 6 feet apart
(depending on cultivation equipment) and callused cuttings should be
lined out about 9 inches apart in the row. Cuttings must be set
right-side-up in the nursery row in a vertical position, rather than
slanting. They should be set with almost their entire length covered
with soil and kept moist until they are growing rapidly. Plants will
be ready for digging the following winter.
Muscadines. Layering is a common method of propagating muscadines.
Peg a long cane into a trench dug in the ground in June, leaving the
cane attached to the vine. Cover it with soil, leaving the shoot
tips exposed. In the winter the layers are uncovered and rooted
shoots are separated from the mother cane. Softwood cuttings (taken
in June or early July) can be successfully grown if propagated under
intermittent mist. This method is becoming very popular for rooting
10. Should bunch and muscadine graces be grafted on a rootstock?
Answer. Improved vigor and yield in 'Stover' and 'Roucaneuf' bunch
grapes results from grafting on a vigorous rootstock. 'Lake Emerald'
and 'Blue Lake' perform well on their own roots under most conditions.
Where grafting is done, 'Dog Ridge' is recommended as a rootstock for
Florida bunch grapes because of its resistance to nematodes. Musca-
dines are more difficult to graft, but generally grow well on their
own roots and seldom require grafting.
11. What is the recommended procedure for grafting grapes?
Answer; 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, is recommended.
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 healthy vines. A graft
scion should be 5 to 8 inches long with 2 or more buds and 1/4`-3/8"
diameter. The portion of the scion to be inserted in the cleft should
be cut carefully to a long, tapering wedge, preferably slightly
thicker on one side. The wedge cut should be started just below the
basal bud on both sides. The scion should be inserted carefully into
the cleft so that the cambium on its thicker edge and that of the
stump coincide. The pressure 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.
Grafts are mounded with soil to prevent drying of the scion. To
protect the soil cover from erosion by wind and rain, a cylinder of
tar paper (10-.12' diameter, 7' high) may be placed over the graft and
filled with clean, moit. soil up to the top bud of the scion. During
dry periods watering may be necessary as often as once a week. The
grafted vine should be trained to a single shoot on a stout permanent
stake attached to the trellis wire. The tar paper should be removed
after scion growth exceeds 15 inches up the stake.
12. Are soil _,ypnes 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 sands and
upland soils, especially those with underlying clay at about 3 feet,
are ideal for grapes. A deep sand with more than 7 feet to clay is
a poorer soil for grapes.
Soils less adapted to viticulture are the white sands, e.g., St. Lucie,
Leon and St. Johns. Immokalee fine sand can be used if bedded and
irrigated. Hard red clay, any poorly drained soils, marl, peat, muck
and peaty muck are not recommended.
Growers should avojd planting grapes in pockets having poor air
drainage, for late spring frosts may destroy tender shoots and blooms.
13. Should li:d for grapes be prepared ahead of time?
Answer: Yes, when possible. Frequently a summer cover 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 grape-
vines are set. Dolomite at 5 pounds per 10 x 10-foot area may be
desirable on new land if calcium and magnesium are limiting and soil
is more acid than pH 5.5. In level, poorly drained soil prepare beds
of soil 16 in. high. and 4 ft. wide, and plant grape plants down the
center of the bed.
14. In what direction should rows be laid out?
Answer: North to south is preferable so that both sides of the vine
will get sunlight at some time during the day. East-west rows have
been successfully used where land use demanded it. With overhead
trellises leave the east side open for exposure of the fruit to
15. What spacings between rows and plants are recommended?
Answer: The following spacings and resulting vines per acre are
most commonly used:
Between plants Vines
rows in row per acre Variety
10 ft. 9 ft. 484 Lake Emerald and Blue Lake
10 ft. 8 ft. 544 Stover and Roucaneuf
Between plants Vines
rows in row per acre Remarks
15 ft. 15 ft. 193 For overhead trellis
10 ft. 16 ft. 272 For 1 or 2-wire vertical trellis
10 ft. 18 ft. 242 For 1 or 2-wire vertical trellis
12 ft. 16 ft. 227 For 1 or 2-wire vertical trellis
16. At what time in the year should grape nursery vines be
transplanted to the vineyard rows?
Answer: Transplanting during dormancy (Jan.-Feb.) is recommended for
bare-rooted plants. Plants in containers may be transplanted at any
time of year.
17. How should a grapevine be planted?
Answer: Set the young bunch grape plant at the same depth that it
was growing in the nursery. Deeper setting is required for musca-
dines planted on well-drained soil because of their susceptibility
18. Should compost or other fertilizers be used when the vine
Answer: Use only 1/4 pound steamed bonemeal or peat moss around the
roots at time of planting. Wait until the young plant has begun
growing before applying other fertilizers.
19. Should a trellis be in place before the vineyard is planted?
Answer: It is desirable to erect the trellis any time prior to one
month after planting so that vines can be trained the first season.
An alternative plan is to grow plants like bushes the first year,
and train to a trellis the second year. This defers the need for
posts by 1 year and permits cross cultivation.
20. What type of trellis is recommended for Florida bunch grape
and muscadine varieties?
Answer: Bunch grapes. A 2-wire trellis, using No. 9 or No. 10
galvanized steel wire, can be constructed on 7-foot copper-treated
posts set 2 feet into the ground. End posts should be 8 feet long
and set 3 feet into the ground, with bracing to carry the heavy
trellis load. Space the posts to accommodate 3 vines between posts.
The bottom wire should be 2.5 feet above ground level (stapled to the
side of the post), while the top wire should be 5 feet above ground
level (stapled to the top center of the post).
Where 4 to 8 vines are planted and shade is desired, an overhead
arbor, with vines planted around the perimeter of the arbor, is
sometimes preferable to a 2-wire trellis.
Muscadines. Space the posts so that only one vine is planted midway
between posts in the row. The 1 and 2-wire systems are the most
common vertical trellises. For the l--wire type place the wires at
5 feet height and for the 2-wire system set them at 2.5 and 5 feet.
The overhead trellis with all wires 7 feet high may be used where
shade is desired, or where maximum fruit yields for a small area are
needed. The Geneva Double Curtain trellis may also be used, with a
cross-arm 4 feet long on each post and one wire mounted at each end
of the cross arm. The two wires run parallel with each other and
are both 5 feet above ground level.
21. How are young plants trained the first year?
Answer: Set a 5.5-foot stake by each plant and wire it permanently
to the top wire of the trellis. As shoots begin to grow from the
set plant, select the healthiest one and secure it to the stake with
twistems or raffia. Remove all other shoots. As the selected shoot
grows, it eventually becomes the trunk of the vine. It is important
to keep it growing straight up the stake by (a) tying often, and (b)
removing all lateral and base sprouts often. Be sure to leave at
least one lateral shoot to grow each way on the bottom trellis wire.
When the shoot reaches the top wire it should be cut off so that
laterals will grow each way along the top wire.
When stakes are not available, tie synthetic baler twine from the
stub of a newly set plant to the trellis wire. The strongest shoot
is then selected to be trained up the twine to the trellis wire as
22. What are the irrigation requirements for grapes?
Answer: Many first-year grape plants have died in Florida vineyards
due to lack of soil moisture. Young plants need irrigation in order
to establish good root systems and grow to the trellis wire. After
the vines have covered the trellis framework they can grow satis-
factorily without irrigation because by that time the roots have
grown deeply enough to reach moist soil even during dry periods.
However, irrigation is beneficial between bloom and harvest on
mature grapevines for increased berry size and fruit yields.
Young vines can be watered with overhead sprinklers, but less water
is required using a trickle (drip) system with an emitter near each
plant or by placing water in a soil basin around each plant when
needed. Mature vineyards, if irrigated, are best watered by a
permanent overhead sprinkler system with risers mounted on trellis
posts where needed. Consult an irrigation specialist before installing
the system, since considerable planning and expense are involved.
23. When is dormant pruning done?
Answer: Pruning is done when the leaves have fallen and the vines are
dormant (usually Dec."-Feb.). Early pruning hastens bloom and ripening
the following season, whereas late pruning (Feb. early March) delays
bloom and ripening times. 'Bleeding" of grapevines is not harmful
if pruning is done when vines are dormant.
24. How should grape vines be pruned?
Answer: Bunch grapes. Vines that fail to reach the top wire during
the first year should be pruned back to two buds near the ground.
Vines that reach the top wire during the first year should be pruned
to a single cane of 3 to 5 buds along each wire in each direction.
After the second year, leave four new wood canes (one for each
direction on each wire) with 8 to 12 buds on each cane. The older
and more vigorous the vine, the greater the number of buds that can
be left on each cane at pruning time. In addition to the four canes,
leave short, 2 to 3-bud spurs near the points of cane origin (near
the trunk) for renewal of canes the following year.
Muscadines. The spur system with permanent arms is used in musca-
dines. Remove tendrils and all branches not needed for spurs and
fruiting arms. Prune all the branches that are less than 3/16 inch
in diameter, leaving 2 to 3 buds per spur depending on the diameter
of the branch. Remove most of the spurs located at the top of the
trunk in order to prevent crowding and business, which will interfere
with harvest. Renew arms that are no longer vigorous.
25. 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', 'Roucaneuf', 'Stover',
'Blue Lake', and muscadines 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: The pH and nutrient status of the soil should be determined
by soil analysis prior to planting. Highly acid soils can be brought
to a more desirable level (pH 6.0) by mixing dolomitic limestone in
the soil at about 5 pounds per 100 square feet of area. About 1/4
pound steamed bonemeal (mixed with soil around the roots) should be
applied at planting time. The first year apply 1/4 pound of 6-6-6 or
8-8-8, with 20%-30% of the nitrogen from natural organic sources, in
two lateral bands one foot away from the plant soon after growth
begins. Repeat this application monthly, ceasing on September 1 in
order to encourage dormancy.
In the second year apply 2/3 pound of the same mixture broadcast in
February (March for-muscadines), May and just after harvest. Rates
can be progressively increased in future years, but do not exceed
4 and 7 pounds per v-ne per year for bunch and musc-adine'grapes,
respectively. Split applications are more efficient than a single
application of the full amount. Good weed control is essential to
get maximum benefit from fertilizers and irrigation.
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 and increase yields. Spraying of bunch grapes should
begin in the spring when buds are about 2 inches long and be continued
at intervals of 10 days to 2 weeks until berries have attained maximum
size; after harvest spray every 3-4 weeks through November or until
Benlate, Manzate D, Dithane M-22 Special, Captan, or Phaltan are
effective fungicides for the control of foliar diseases on grapes in
Florida. Benlate is approved for control of black rot, bitter rot,
powdery mildew, and bunch rot but may not be applied within 7 days of
harvest. Manzate D and Dithane M-22 Special are approved for control
of black rot but may not be applied within 7 days of harvest. Phaltan
is approved for black rot, downy mildew, and powdery mildew; and
captain for black rot, downy mildew, and bunch rot. Benlate is applied
at 0.5-1.5 pounds per 100 gallons of water per acre (1/2 to 1 table-
spoon per gallon). Manzate D and Dithane M-22 Special are applied at
1.5 pounds per 100 gallons of water (1 tablespoon per gallon) and
Captan and Phaltan at 2.0 pounds per 100 gallons (1 1/2 tablespoons
per gallon). Addition of a spreader material (e.g. Triton B-1956) is
desirable. A winter spray of lime sulfur, 2 quarts of a 26 to 31%
solution per 100 gallons (1 1/4 tablespoons/gal.), may be applied to
help control anthracnose on bunch grapes.
Muscadines also need to be sprayed in Florida if a good crop of
quality grapes is desired. Black rot and bitter rot can cause large
losses if vines are unsprayed. Spraying of muscadines should start
at flowering and continue until 7-10 days prior to harvest; the
fungicides and rates are the same as for bunch grapes.
Recommended insecticides and rates are shown in the following table:
Material Formulation 100 gallons 1 gallon harvest*
Malathion 55-57% EC 1 quart 2 teaspoons 3
25% WP 4 pounds 4 tablespoons 3
Sevin 50% WP 2 pounds 2 tablespoons 0
80% WP 1 1/4 pounds 4 teaspoons 0
S-Do not apply after this time.
Any of the above may be used for caterpillars, beetles and leaf-
hoppers. Malathion is used for aphids.
READ THE LABEL. BEFORE USING FUNGICIDES, INSECTICIDES, HERBICIDES
OR ANY AGRICULTURAL CHEMICAL BECOME THOROUGHLY ACQUAINTED WITH
DIRECTIONS ON THE LABEL AND FOLLOW THEM EXACTLY SINCE MANY OF THESE
CHEMICALS ARE POISONOUS TO MAN AND ANIMALS. ALSO, INJURY TO THE
CROP MAY RESULT FROM IMPROPER USE.
28. What type of cultivation or herbicides are required in a
Answer: One of the secrets of successful grape growing is an inte-
grated program of weed control involving mechanical tools, herbicides
and mulches. Weed control between vine rows is much easier to
accomplish than that under the trellis itself. Herbicides are rarely
used for weed control between rows since disking, rototilling, or
mowing are more practical and less expensive both in young vineyards
and mature vineyards. The discussion below concerns control of weeds
in the vine row where disking and mowing are not possible.
Young vineyards. Mulching with 2 to 3 inches of oak leaves around
each newly set grapevine helps control weeds and conserve soil
moisture. Hoeing of weeds in small vineyards is usually replaced by
Paraquat spraying or in-and-out rototilling, or both, in vineyards
one acre or larger. Paraquat kills all the leaf surface it covers,
including grapevine foliage. A tractor-mounted boom with a nozzle
surrounded by a cone-shaped shield to prevent drift of spray in windy
weather is effective in directing the material to a band along each
side of the row without getting on the grape plants. Sufficient
overlap of spray bands between vines in the row is essential to avoid
leaving a green strip of weeds under the trellis wire. The in-and-out
vineyard rototiller (Hester Plow Company, Lake City) is mounted on the
side of the tractor and operates from the power take-off. It is very
effective in controlling both broadleaf and grassy weeds in the vine
row. Dalapon herbicide controls grassy weeds. Apply in April or May,
or when the grass is green and actively growing. Avoid spraying the
Mature vineyards (3 years or older). Karmex (Diuron) herbicide is an
effective pre-emergence herbicide if applied once a year, usually in
March. Weed growth occurring in the rows in mid- to late summer can
be -burned down' with Paraquat herbicide, hoed, or in-and-out roto-
tilled. Dalapon is effective on grassy weeds such-as Bermuda grass
sod. Do not mix Dalapon with other herbicides in the spray tank.
Karmex and Paraquat may be mixed where both a ore-emergence and
"burn-down' of existing weeds are needed at once. Thorough cleaning
of spray tank, hose, and nozzles by draining, flushing, and cleaning
with detergent are recommended following the use of herbicides.
Herbicides used for grapes
1 qt./50 gal.
5 lbs./50 gal.
Amt. of X-77
4 oz./50 gal.
4 oz./50 gal.
Wet above-ground portion
of weeds whenever needed
(3 to 5 times a year)
Wet leaf surface when grass
is actively growing (twice
each year, 3 weeks apart)
Karmex 80W 3 Ibs./sprayed None required Wet surface of ground evenly
(diuron) acre in a band on each side of
2 tsp./gal./ row (once each year, usually
100 sq. ft. March). Vines must be 3
yrs. old and 1 1/2 inches
1 Caution: muscadine grapes are subject to injury by Dalapon if the
ground is bare and th. material is taken up by the vine roots.
29. What can be done to protect grapes from birds and other pests?
Answer: Stretching nylon netting (1i mesh) over the vines during the
time of fruit ripening, or attaching baby chick wire to a framework
enclosing the vines are means of excluding birds from the vines.
Individual clusters may be enclosed in brown paper bags, cheesecloth
bags, or in envelopes made of screen wire. A 3-foot fence around the
perimeter of the vineyard with an electrically-charged wire at the
top will exclude four-footed animals except deer.
Scare devices such as acetylene or propane bombs, a string of fire
crackers on a slow-burning fuse, tin can lids suspended on strings,
or brightly colored plastic propellers that rotate when the wind blows
may scare some birds, but are generally not effective on mockingbirds.
Extermination by shooting, poisoning and trapping can be effective,
but federal, state and local laws should be observed. Pests such as
rats, raccoons and rabbits can be eliminated by poison bait placed in
the vicinity of the damage.
30. Where can I find more information about grapes?
Answer: The following are for sale by the Supt. of Documents, U. S.
Govt. Printing Office, Washington, D. C. 20402:
1. 'Growing American Bunch Grapes,; 1973, U.S.D.A. Farmers Bulletin
2. "Control of Grape Diseases and Insects in the Eastern United
States,- 1968, U.S.D.A. Farmers Bulletin 1893.
3. "Muscadine Grapes, a Fruit for the South,;; 1971, U.S.D.A. Farmers
A general reference on grapes is the following book:
Winkler, A. J., J. A. Cook, W. M. Kliewer, and L. A. Lider. :General
Viticulture'. Univ. of Calif. Press, Berkeley, 1974, pp. 710, $28.
The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University