Chapter 2 - The Vine Growth Cycle Flashcards
Dormancy:
Months
Needs
Adverse Conditions:
November - March (leaf fall - budbreak)
Temp below 10C
Extreme cold or mild temps
During dormancy, temps below what will kill vines?
-25C
Budburst:
Months
Needs
Adverse Conditions:
March - April
Avg air and soil temps above 10C
Frost, cold soils
Factors that affect when budburst happen
Air temp
Soil temp
Grape variety
Human factors
Why is continental climate beneficial for bud burst? Why is mediterranean climate not?
Because it has marked differences in temperature between seasons
Rapidly increasing temps in the spring means uniform budburst, means even ripening later on
Mediterranean climates don’t have a marked difference in temp
Also, mild winters are often and they can cause early budburst. Any frost or dip in temp after that can harm/kill the buds. Leads to lower yields
What kind of soil is advantageous for budburst? Why?
Sandy soils - bc it is dry, free-draining, and warms up quicker than water storing clay. Especially advantageous in cool climates
What are early budding varietals? Example?
Ones taht require relatively low temps at budburst (ie Merlot)
What are late budding varietals? What’s the pro of them?
Late budding: Sauv Blanc, Cab, Syrah
Less risk of spring frost
What is a human activity that can delay budburst?
Carrying out winter pruning later in the dormant period. Can be used to prevent spring frost
Shoot & Leaf Growth
Months
Needs
Adverse Conditions
March-July
Stored carbs, warmth, sunlight, nutrients, water
Low carb levels, water stress
What is plant vigor dependent on?
Natural resources available (sunlight, water, nutrients, warmth)
Planting material (varietal, rootstock, clone)
Presence of disease
How do low carb storage and water stress negatively affect vine growth?
Stored carbs are important for initial shoot growth and providing the necessary sugars until the leaves grow and are able to perform photosynthesis
Vines that suffer from water stress at this time can limit photosynthesis and shoot growth
Shoot growth is MOST IMPORTANT at this stage
What can cause low carb storage levels?
In the previous growing season: Excessive leaf removal Water stress Mildew infections Excessively high yields
Flowering & Fruit Set
Months
Needs
Adverse Conditions
May - June
Warm temp (min 17C)
Sunlight, warmth, water, nutrients - for bud fruitfulness in the next growing season
Cold temp, wind, rain, cloudyness
What will cause limited bud fruitfulness?
Shading of the compound buds, water stress, nutrient deficiency, low temps under 25C