Chapter 5: The Growing Environment

Question 1

List the five factors needed for a vine to complete its annual cycle

Answer 1

Heat (below 10oC the vine won’t grow. Enough heat needed for successful flowering, fruit set, ripening)
Sunlight (for photosynthesis)
CO2 (for photosynthesis)
Water (for photosynthesis)
Nutrients (to support growth and ripening)

Question 2

List factors affecting heat

Answer 2

Latitude
Altitude
Ocean currents
Fog
Soil
Aspect

Question 3

At which latitudes are most vineyards found?

Answer 3

30o-50o North and South of the equator

Question 4

What effect does altitude have? Give an example of a region where this is relevant.

Answer 4

Higher altitudes = colder. Regions that are closer to the equator can compensate by planting vineyards at higher altitudes e.g. Cafayate in Northern Argentina

Question 5

What effect do ocean currents have? Name the most relevant global currents to the wine industry and whether they have a warming/cooling effect.

Answer 5

They have localised warming or cooling effects as they carry large volumes of warm or cool water around the ocean surface.
Humboldt Current - Chile (cooling)
Benguela Current - South Africa (cooling)
Gulf Stream - NW Europe (warming)
Californian Ocean Current - fogs on west coast of North America (cooling)

Question 6

What effect does fog have? Give an example of a region where this is relevant.

Answer 6

Helps cool areas. Examples are California and Casablanca Valley in Chile

Question 7

What effect does soil have on warmth in the vineyard?

Answer 7

Darker coloured soils or those with high stone and rock content help absorb and reradiate heat from the sun, which helps ripen fruit.
Soils with high water content need more energy to warm up and help conduct heat away from vine. Can delay budburst.

Question 8

What effect does aspect have? Give an example of a region where this is significant.

Answer 8

An equator-facing aspect receives the most heat. Important in cool climates where extra warmth helps ripen a crop. A steeper slope also benefits from this effect.
E.G. Mosel in Germany has both South-facing and steep aspects.

Question 9

Define continentality and why it’s important to grape growing.

Answer 9

This is the temperature difference between the hottest and coldest months for a region. A region’s continentality will determine the length of the growing season as it impacts the total amount of heat available to a vine. This, in turn, influences which varieties can be grown in a region.

Question 10

Explain the effect of bodies of water on continentality

Answer 10

Regions which are closer to large bodies of water typically have lower continentality because water warms up and cools down more slowly than landmasses (in Winter have a warming effect, in Summer a cooling effect).
Therefore regions further inland and away from bodies of water typically have higher continentality (more temperature extremes).

Question 11

What is a diurnal range? How does a wide or narrow diurnal range affect grape growing?

Answer 11

A diurnal range is the difference in temperature between nighttime and daytime.
Cooler nights help slow loss of aromas and acidity in grapes during ripening - a wide diurnal range in a vineyard can produce fresher and more aromatic wines in an otherwise warm or hot climate, compared to a vineyard with a small diurnal range.
Note: warm nights accelerate ripening, and therefore decreased acidity.

Question 12

Explain the effect of bodies of water on a diurnal range

Answer 12

Close proximity to bodies of water can reduce a diurnal range as they can hold enough warmth to warm adjacent vineyards overnight and provide cooling breezes during the day.
There also tends to be more cloud cover nearer to seas and lakes which helps insulate against large temperature fluctuations (temperatures typically drop more quickly on nights with clear skies, and rise more slowly on cloudy days as sunlight cannot reach the ground directly)

Question 13

Describe the temperature-based hazards of Winter on a vineyard

Answer 13

If temperatures drop below -20oC, the vine can be seriously damaged or die. As the graft is the most vulnerable part, earth can be used to cover it up in process called ‘earthing up’.
A mild or non-existent winter (in subtropical climates) means the vine will not have a dormant period and may produce more than one crop per year, which shortens its life and produces lower quality grapes. Mild winters also increase the population of insect pests which attack the vine the following summer.

Question 14

Describe the temperature-based hazards experienced in Spring on a vineyard

Answer 14

Cooler Spring temperatures may delay budburst. This shortens the growing season, meaning there isn’t enough time for grapes to ripen fully in Autumn before it gets too cold. It can also disrupt flowering and fruit set, leading to smaller than average grape crops.

E.G. Spring frost: occurs when cold air <0oc settles on the ground/vine which kills newly-burst buds or young shoots. This has a serious impact on yields.

Question 15

List the mechanisms to combat Spring frost

Answer 15

Heaters - placed throughout vineyard, generated heat creates movement in the air to prevent cool air settling
Wind machines - draws warm air from above to warm cool air below. Widely used, some incorporate heaters.
Sprinklers - sprays water onto vines. As water freezes it releases some heat into plant tissue, protecting buds and shoots.
Thoughtful vineyard design - plant vineyards on slopes and avoid depressions where cool air collects. Mid-slope is noticeably less at risk than lower areas. Also train vines high.

Question 16

Describe the temperature-based hazards experienced in Summer in a vineyard

Answer 16

Very hot temperatures/prolonged extreme heat will slow all vine activity and eventually stop it (even if there is sufficient water), preventing proper ripening and eventually killing the vine in extreme cases.

Question 17

Benefits of sunlight on a vine

Answer 17

More light means more photosynthesis, and generally-speaking therefore more glucose for growth and ripening
Flowering and fruit set benefit greatly from plenty of sunlight

Question 18

List factors that can affect the amount of sunlight experienced by a vineyard. Give examples of regions where this effect is marked.

Answer 18

Latitude - day length is longer when vineyard is further from Equator e.g. Riesling in Germany benefits from ripening
Seas and lakes - more cloud cover closer to bodies of water (less sunlight), less cloud cover further inland (more sunlight). Also reflection off bodies of water can benefit vines e.g. German vineyards planted on slopes facing Rhine.
Aspect - facing equator means more sunlight, helpful for regions further away from equator which receive weaker sunlight e.g. Germany south-facing slopes tend to be best vineyard locations

Question 19

List hazards associated with sunlight

Answer 19

Lack of sunlight:
-Cloudier periods than usual can result in unsuccessful flowering and fruit set, and therefore smaller crops of grapes.
-Cloudy periods can also slow photosynthesis and therefore stop grapes from ripening fully.
Too much sunlight:
-Intensely sunny conditions can burn grapes, leading to bitter tastes from grape skins

Question 20

Describe the process of water uptake by a vine, and why limiting water supply can be beneficial to vine growing.

Answer 20

A vine takes up water through its roots, and draws water up to its leaves via transpiration. Temperature determines how much water a vine needs i.e. warmer temperatures means water evaporates at a faster rate from its leaves, meaning the vine takes up more water from the soil to compensate. Once a sufficient canopy of leaves has grown (to photosynthesise), limiting water tends to be beneficial for grape growing.

With limited water availability, the vine can continue photosynthesising but will limit further shoot and canopy growth (preventing shading), allowing it to concentrate more on grape ripening. This also reduces the impact of shading from excessive canopy growth.

Question 21

List and describe forms of irrigation

Answer 21

Drip irrigation - most advanced and expensive. Drippers can be computer controlled, and each vine gets an optimum amount of water.
Sprinklers - widely used, cheaper than drip irrigation, but waste water and create damp conditions which increase disease risk. Could be used for frost protection if correctly designed.
Flood irrigation - very cheap, only possible in flat/gently sloped vineyards and where access is available to large quantities of water.

Question 22

What hazards are related to water, and how do we mitigate them?

Answer 22

Drought - water shortage causes vine to temporarily stop transpiration. In prolonged periods of drought = water stress: photosynthesis stops, leaves wilt and grapes don’t ripen. Ultimately can weaken and kill a vine. Can mitigate by irrigation.

Too much water - vine will continue to grow shoots and leaves during ripening season, leaving less sugar for ripening grapes. Increased shading also restricts ripening. Extreme conditions (waterlogged soil) oversaturates roots and kills them. Can mitigate by planting vines on slope or installing drainage pipes.

Timing of rainfall:

• During flowering and fruit set can cause disruption, and dampness can spread fungal diseases.
• Heavy rain before harvest causes swelling in berries and dilutes flavours, also causing splitting and fungal disease.

Hail - can damage or destroy entire crop. Mendoza is prone to hail. Mitigate by netting (expensive), or as hail storms are localised, own several vineyard sites in different locations.

Question 23

Define climate

Answer 23

The annual pattern of temperature, sunlight, and rainfall average out over several years. Climate cannot change from one year to the next, but can alter over decades.

Question 24

Define weather

Answer 24

Annual variation that happens relative to the climatic average.

Question 25

Define a cool climate

Answer 25

Average growing season temperature of 16.5oC or below

Question 26

What is the growing season for Northern and Southern Hemisphere?

Answer 26

Northern Hemisphere - April to October

Southern Hemisphere - October to April

Question 27

Define a moderate climate

Answer 27

Average growing season temperature of 16.5oC - 18.5oC

Question 28

Define a warm climate

Answer 28

Average growing season temperature from 18.5oC to 21oC

Question 29

Define a hot climate

Answer 29

Average growing season temperature above 21oC

Question 30

Define a continental climate with examples of regions and its effect on vineyard growth and varieties

Answer 30

Has the greatest difference in temperature between hottest and coldest months, typically defined by short dry summers with large, rapid temp drop in autumn. E.g. Chablis and Champagne are at risk of Spring frost, and low temperatures throughout growing season can affect flowering, fruit set and ripening. These regions are better suited to early-ripening and late-budding varieties e.g. Chardonnay.
Also dry summers with high temperatures may mean irrigation is necessary.

Question 31

Define a maritime climate with examples of regions and its effect on vineyard growth and varieties

Answer 31

Cool to moderate temperatures and low continentality. Evenly spread rainfall throughout the year helps moderate temperature. Temperatures are warm enough for grapes to continue ripening far into autumn. E.g. Cabernet Sauvignon with its thick-skin successfully ripens in Bordeaux, where it would otherwise struggle to ripen at these latitudes.
Note rainfall in spring and summer can be harmful to flowering, fruit set, and health of grapes at harvest.

Question 32

Define a mediterranean climate with examples of regions and its effect on vineyard growth and varieties

Answer 32

Low continentality but summers tend to be warm and dry. E.g. Coastal California, Chile, South Africa, SE Australia, Greece. Extra warmth and sunlight leads to fuller bodied wines with riper tannins, higher alcohols, lower acidity. Lower rainfall can have positive effect on health of grapes but can lead to drought.

Question 33

List the main components of soil

Answer 33

Stones, sand, clay and humus

Question 34

What is humus?

Answer 34

Organic matter made up of decomposing plant/animal materials, provides plant with nutrients and is excellent at retaining water

Question 35

Why is soil composition so important with respect to water and nutrient availability?

Answer 35

There is a fine balance between particle sizes, nutrients and water retention. Water is stored in soil by binding to clay particles or humus: too much clay leads to waterlogging, too much sand/stone leads to water drainage. Vines need a lot of water early in the growing season to support strong shoot and leaf growth, followed by mild water stress after veraison.

Question 36

What is considered to be one of the best soil compositions? Why?

Answer 36

Loam - good drainage, but retain enough water for vine growth. Of course the benefit of this composition depends on climate and weather of a region.

Question 37

List the three nutrients most important for a vine

Answer 37

Nitrogen, phosphorous, potassium

Question 38

What happens if a vine has too many nutrients?

Answer 38

Vine grows to vigorously, producing a dense leafy canopy that shades fruit too much.

Question 39

What happens if a vine has too few nutrients?

Answer 39

Chlorosis - leaves turn yellow and vine’s ability to photosynthesise is restricted. Quality and quantity of grapes are decreased. Using appropriate fertiliser can solve this problem.