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Introduction to Vines and
Wines
Hort/VE 113 Fall 2012
Session 7-Grape Growing
pruning
Lesson Objectives:
Learn the importance of
pruning in vine and crop management
Understand how pruning affects
crop l d and vegetative growth
load d t ti th
Understand how pruning levels
affect fruit quality
Concepts of Pruning
What is pruning? What is the difference
between pruning and training?
Pruning is the removal of unwanted wood
or parts of the vine…and
f h i d
Training is the establishment of the
permanent vine structure or form.
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Why prune?
1. Establish and maintain vine structure
and cropping
2.
2 Distribute crop load
3. Control and adjust crop load
4. Maintain or control vegetative growth
The objective of pruning is to
maintain a balance between
fruiting (crop load) and
vegetative growth (canopy)
Another important factor to consider in HOW
MUCH to prune is “vigor” and “capacity”.
Vigor--rate of growth; often used as an indicator
of vine “health”.
Capacity--quantity of total growth and total crop
of which the vine or part of the vine is capable
of producing.
Growth—irreversible change in size (weight,
height, etc.)
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If the capacity of the vine is dependent on
vigor, how can we manipulate capacity with
pruning?
Some general concepts of vine pruning:
m g p f p g
1. Amount of wood removed--generally 70% to
90% of last season’s growth is removed. The
purpose of wood removal is to keep vine
structure intact.
Cane
Cordon
Trunk
Spurs
Removed
Wood (canes)
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Spur system
Buds
Cordon
Each bud on the spur
gives rise to the
Cordon
shoot and fruit
for the current
season
New shoot +
Flower clusters
Spur
New shoots emerge
In mid‐ to late April
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2. Cane and bud quality--pruning involves
careful selection of buds for growth and
fruiting.
Amount of light exposure affects bud
quality and fruitfulness (i e capacity).
(i.e., capacity)
Another concept related to pruning that is
used with grapevines is “balanced pruning”.
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6. 9/14/2012
“balanced pruning”
Relates the capacity of the vine in terms of
crop load with the number of buds retained on
canes or spurs on the vine.
Called balanced pruning because the yield of
p g y
the vine is in balance with the vegetative
growth and carbohydrate reserves (storage).
Balanced pruning is removal of vine growth
according to a calculated number of buds for
CROP !
Important things to consider:
A typical vine produces 200 to 300 buds
capable of fruiting (after a season’s growth).
How many buds are normally left for
y y
production?
Vigor (the inherent growth rate) dictates
the number of buds left. On average, about
35 to 40 buds per vine are left for cropping.
Pruning too lightly leads to:
• Excessive shoot growth
• Shading problems
• Poor fruit quality
• Reduced vine vigor
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7. 9/14/2012
Overcropping leads to:
Delayed or inadequate fruit maturation
Reduced vine size (and y
( yield potential)
p )
Reduced hardiness
What would undercropping do to yield
and vine growth?
Response of the Vine to Pruning and Cropping
•Active leaf area determines the amount,
,
composition and quality of the crop.
•The floral parts differentiate after vegetative
growth begins in the spring.
Is severe pruning invigorating?
-Increases the rate of individual shoot growth.
-Less severe pruning improves vine capacity for
g
growth and production.
p
-Fruit quality improves with crop thinning as
appropriate.
-A Function of leaf area as source, and the
fruit as sink.
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Source: Winkler et al: General Viticulture
Canopy differences due to
shoot density. Notice a
Diagram of two difference?
‘grapevines’ having the
same amount of canopy,
but vine B having twice
the amount of fruit.
Winkler devised the following “Principles
of Pruning”:
1. Pruning is dwarfing.
•Decreases total productive ability of
the vine
•Decreases capacity (leaf area)
Decreases
To the grower:
* Pruning concentrates the
activities into the parts that remain.
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9. 9/14/2012
“Principles of Pruning”:
*Pruning diminishes the total capacity of the
vine for growth and crop.
2. The crop depresses the vine’s capacity
for the following year (or years).
3. The capacity of the vine varies directly
with the number of shoots that develop.
* The total active leaf area, not the
rate of shoot elongation, determines
capacity.
“Principles of Pruning”:
4. The shoot vigor varies inversely with
shoot number and crop load.
5. Fruitfulness (within limits) varies
inversely with shoot vigor.
Refer to Fig. 79.
Source: Winkler et al: General Viticulture
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“Principles of Pruning”:
6. A large cane, arm or vine can produce more
than a small one, and therefore should carry
more fruit buds.
* Capacity is directly proportional t t t l
C it i di tl ti l to total
growth.
7. A given vine in a given season can properly
nourish and ripen only a certain quantity of fruit.
Its capacity is limited by its cropping history and
its environment.
* the maximum crop that a vine will bear without
delaying maturity is its index to its bearing
capacity. We think of this crop being a “normal”
crop load.
When choosing which canes to leave for fruiting
fruiting,
there are selection criteria:
 Wood is firm and has good diameter (pencil-
size is often used for reference)
 Wood color
 Internode length
Shoot/cane position: horizontal vs. vertical
Time of pruning:
1. Dormant (leaf fall to bud break)
Time of dormant pruning has little or no
effect on crop potential.
Total CHO’s remain the same—the form
(sugars vs. starch) changes.
2. Summer pruning (during the growing
Season.
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Why is summer pruning so useful?
 Training and shaping -- can direct growth
(disbudding, pinching and suckering)
 To avoid wind breakage (“topping”)
 T improve light distribution
To impr v li ht distributi n
 To provide selective shading on clusters
Spur pruning:
Spur: 2 to 4 buds each
Spurs spaced 8 to 12 inches apart
p p p
Generally leave 35 to 75 buds/vine—cv. and
vigor dependent!
http://www.youtube.com/watch?v=K1vZHwrp8H0
http://www.youtube.com/watch?v=lula7WUoZlo
http://www youtube com/watch?v=lula7WUoZlo
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