Chapter 3 - The Growing Environment - Part 1 Sunlight and Temperature

Question 1

Temp needed to ensure dormancy
Temp that causes winter freeze/ damage to the vines
Temp that will kill the vine

Answer 1

Under 10C
Around -20C
Below -25C

Question 2

Temp that stimulates budburst

Answer 2

Above 10C

Question 3

Temp range for shoots and leaf growth and for photosynthesis

Answer 3

18-33C

Question 4

Temp for uniform flowering

Answer 4

Above 17C

Question 5

Temp for fruit set

Answer 5

26-32C

Question 6

Temp for bud fruitfulness

Answer 6

Above 25C

Question 7

Temp that can cause rapid loss of acidity in final month of ripening

Answer 7

Above 21C

Question 8

Temp that can reduce acid loss to the point that acidity levels are too high

Answer 8

Below 15C

Question 9

Temp for optimal anthocyanin synthesis

Answer 9

15-25C

Question 10

How does sunlight affect grape growth?

Answer 10

Enhances development of anthocyanins
Reduces levels of methoxypyrazines
Greater accumulation of tannins pre-veraison and tannin polymerization after veraison
Increases levels of favorable aroma precursors/compounds
Increases rate of malic acid use (good and bad)

Promotes successful fruit set
Promotes budfruitfulness

Question 11

Amount of sunlight actually needed. What does it affect below that threshold?

Answer 11

1/3 of full sunshine - below that it affects photosynthesis

Question 12

Cons of too much sunlight

Answer 12

Sunburn - affects quality and yield

Question 13

Why are regions in lower latitudes warmer and have more sunshine, generally?

Answer 13

Solar radiation hits at a higher angle and travels thru a smaller section of atmosphere

Low latitude regions receive similar daylight hours throughout the year. High latitude regions have longer daylight hours in the summer and shorter in winter

Question 14

What is the ideal latitude range for viticulture?

Answer 14

30-50deg

Question 15

What does high-altitude sites have that low altitude sites don’t, generally?

Answer 15

Lower temp (temp falls 0.6C over every 100m increase
More intense solar radiation - radiation tarvels thru less atmosphere to reach the site - promotes anthocyanin and tannin synthesis
More ultraviolet radiation - promotes anthocyanin and tannin synthesis
High diurnal range - thinner air holds less moisture and therefore heat escapes rapidly

Question 16

How does aspect help viticulture in high latitudes?

Answer 16

Increases the angle at whcih solar radiation hits the earth’s surface, increasing hte heat and light intensity

Question 17

What are the benefits to east facing vineyards?

Answer 17

Direct morning sun heats up first and gets more sunlight hours in
Direct morning sun dries environment and prevents fungal disease from spreading

Question 18

General pros/cons of slopes

Answer 18

Pros:
Shallower, poorer soil
Better drainage
Shelter from winds and rains
Protection from frost (cold air moves down)

Cons:
Machinery hard to use/not possible to be used
Soil erosion

Question 19

How does being proximal to water help the Finger Lakes and Carneros?

Answer 19

Finger Lakes:
Lake milds out winters by retaining and warming up the land by it - cool summers, mild winters
Also prevents frost by providing constant air movement

Carneros:
Cooling oceanic wind in the afternoon because water remains relatively cool compared to land

Water heats up and cools down slower than dry land

Question 20

Warming oceanic currant that warms up Bordeaux

Answer 20

Gulf Stream

Question 21

Cooling oceanic current that cools down Oregon

Answer 21

Califonia current

Question 22

Pros/cons of winds and breezes

Answer 22

Reduces humidity and stagnant air - good for fungal disease prevention
Valleys that face the coast help winds travel farther inland (petaluma gap)

Increases evapotranspiration for the vine
Strong winds can damage vines and trellising
Winds that travel over hot land masses bring warm air (zonda) - good and bad

Question 23

What factors of soil affect its and the air’s temperature ?

Answer 23

Drainage
Texture
Color

Question 24

What types of soil warm up quicker and waht are the benefits?

Answer 24

Free draining soils - sandy and stony soils
Encourages breakdown of starch, stimulating budburst and shoot growth (therefore wanted in cool climates but can also inc risk to spring frost)

Question 25

Light vs Dark colored soil

Answer 25

Light colored (ie chalk) reflect energy from solar radiation into lower parts of the canopy - beneficial for photosynthesis and grape ripening as these parts may be shaded. In warm climates, can lead to unwanted temp increases though

Dark colored soil (ie volcanic soil) absorb energy and reradiate when the temp cools like at night
Useful for cool climates or late-ripening grapes - allows color dev and acid degradation to continue into the night

Question 26

Impacts of mist and fog

Answer 26

Slows down sugar accumulation and acid degradation

Increases humidity - good for noble rot and fungal disease

Question 27

Diurnal Range definition

Benefit of large diurnal in warm climates?
Benefit of low diurnals in cool climates?

Answer 27

Average difference between day and night time temperatures

Slows down respiration of malic acid and beneficial for anthocyanin formation (too hot during the day)
Grapes can continue to ripen at night - acid degradation, anthocyanin synthesis, etc