VITICULTURE
INTRODUCTION
In this module, we will introduce the basic
terms and concepts of viticulture — the
science of fine wine grape growing. We
will also cover the annual life cycle of the
vine and exactly what a grape vine needs to
thrive and survive during the growing season.
Remember, the growing season is in opposite
months in the Southern Hemisphere.
MODULE OBJECTIVES
In this module you will learn:
•The basic terms and concepts of viticulture —
the science of grape growing
•The anatomy of a wine grape and grape vine
•An introduction to the annual life cycle of
the vine
WHAT IS VITICULTURE
• Viticulture is the branch of agriculture that involves
the science of grape growing.
• It has been said that wine is the second oldest
beverage after water; and grapes have been
cultivated for the purpose of winemaking for
thousands of years.
• It is only within the last century that grape growing
has become elevated to its current status that is a
combination of science and art.
ANATOMY OF A WINE GRAPE
Stem: usually removed before
the grapes are pressed or
crushed. Sometimes stems are
included in red wine fermentation
to increase the amount of
tannins in the finished wine.
Skin: skins of red grapes provide
color and tannin. White wines
are made without skin contact.
The outside of mature grape
may contain up to 100,000
yeast cells which may be used
for fermentation.
ANATOMY OF A WINE GRAPE
Pulp: produces the juice, or
must, as it is called during
fermentation. The pulp
provides water, fruit flavors,
and sugar required for
fermentation.
Pips: or seeds are not
crushed during the winemaking process as they
contain bitter oils which
would spoil the wine.
ANATOMY OF A GRAPE VINE
• Tendril
• Bunch
• Leaf
• Node
• Cane/Arm
• Trunk
• Soil line
• Roots
ANNUAL LIFE CYCLE
OF THE VINE
• Dormancy
• Fruit Set
• Bud-Break
• Ripening of Fruit
• Foliage Development
• Harvest
• Flowering
• Late Harvest
DORMANCY: WINTER
While the vines are dormant during winter, most of the
work in the vineyard involves pruning or cutting back the
canes leaving a few buds for the next season’s growth.
“Weeping” is the first sign of the new growing
season, and takes place in:
•February for the Northern Hemisphere
•August for the Southern Hemisphere
At that time, the soil temperature rises to 50°,
warm enough for the vine roots to begin to collect
water. Then sap rises up through the vine and
oozes from the cane ends which have been
pruned during the winter.
Pruning for spring growth continues at this time
but the vines are very vulnerable to early spring
frosts which can freeze and kill the new buds.
BUD-BREAK-SPRING
In spring, bud-break takes place some
20–30 days after the vine starts to weep.
The exact date varies with different
grape varieties.
•March–April in the Northern Hemisphere
•September–October in the Southern Hemisphere
During bud-break the first new growth of the season
appears. At this time spring pruning continues and the
vines are secured to training wires.
Aerating the soil is another important vineyard activity
and the threat of frost continues.
FOLIAGE DEVELOPMENT:
SPRING
Following bud-break, small shoots emerge from the
vines and tiny green embryo clusters form. These
small clusters will eventually become grapes.
This foliage development happens in spring:
•April–May in the Northern Hemisphere
•October–November in the Southern Hemisphere
At this time the vines are sprayed for pests if
necessary, and the vineyards are fertilized.
FLOWERING: LATE SPRING/
EARLY SUMMER
Flowering of the vines takes place late spring/early
summer, approximately eight weeks after bud-break:
•May–June in the Northern Hemisphere
•November–October in the Southern Hemisphere
The weather must be dry and frost-free,
and temperature is critical:
68°– 77 ° is optimum.
FRUIT SET: SUMMER
Fruit set takes place in summer:
•June–July in the Northern
Hemisphere
•December–January in the
Southern Hemisphere
After flowering the fruit evolves
rapidly, with the exact number
of grapes per bunch varying with the specific
grape variety.
Spraying, summer pruning, and weeding all continue
in the vineyard at this time.
RIPENING OF FRUIT: SUMMER
The fruit begins to ripen during verasion, the stage when the grape
skins change color and the flavors begin to develop. This happens
later in summer:
• August in the Northern Hemisphere
• February in the Southern Hemisphere
During this time the sugar content in the grapes
increases. Also, the tart malic acid in them decreases
while the more important tartaric acid increases.
The seeds of the grapes also begin to mature
as well as the tannins.
In the vineyard spraying and weeding continues.
Leaf pulling and canopy management (trimming the
leaves of the vine to make sure the grapes receive
enough sunlight to fully ripen) also takes place.
HARVEST: LATE SUMMER
THROUGH MID FALL
Harvest takes place late summer
through mid-fall:
•August–October in the Northern
Hemisphere
•February–April in the Southern
Hemisphere
It varies with different locations, specific
grape varieties, and wine styles:
•Generally, whites grapes are harvested before red grapes.
•Harvest for sparkling wine grapes takes place before still
wine grapes.
•Grapes used for late harvest, dessert wines are harvested last.
Harvesting is done either by hand or machine. Most fine wine in
the U.S. is made from hand-harvested grapes.
LATE HARVEST: LATE FALL
THROUGH MID WINTER
Late-harvesting grapes for dessert wines takes place:
•November - January in the Northern Hemisphere
•May - July in the Southern Hemisphere
Some dessert wines are made from grapes affected
with botrytis.
Botrytis is a mold, that forms in some growing
regions under certain conditions. While disastrous
when it develops on red wine grapes (called gray
rot), botrytis is responsible for many of the world’s
greatest dessert wines.
•November in the Northern Hemisphere
•May in the Southern Hemisphere
With the first hard frost, grapes for ice wine are harvested. With
the arrival of winter, the growing season begins again with
dormant pruning.
REVIEW
You should now have a good understanding of:
• The basic terms and concepts of viticulture
• The anatomy of a wine grape and grape vine
• The basic annual life cycle of a vine