Ch 5 - The Growing Environment Flashcards
(34 cards)
Describe the annual cycle of the vine.
In winter the vine is dormant, no green parts on vine.
Budburst marks the start of the growing season in Spring as the new shoots begin to grow.
During late spring/early summer, the vine flowers and small grapes for. This is called fruit set.
As summer progresses grapes grow but are still hard and green with high acid and no sugar.
In late summer/early autumn the grapes start to ripen and increase in water, sugar levels and decrease in acid. Flavour develops.
First sign of ripening is change in colour from green to blue/black, pink or gold depending on variety. This is called veraison.
Season ends with harvest in autumn and vine drops leaves in lead up to winter.
What are the 5 things a vine needs?
- Heat
- Sunlight
- Water
- Co2
- Nutrients
What is the lowest temperature at which grapes can grow?
10 degrees - lower than this and the vine will lie dormant.
Why is heat important?
Heat is required for flowering, fruit set and ripening.
What 7 factors can impact on heat? What is the acronym you can use to remember these?
FOALSAC
1. Fog
- Ocean currents
- Altitude
- Latitude
- Soil
- Aspect
- Continentality and Diurnal Range
How does fog impact on heat?
Can help cool an area otherwise struggling to produce high quality grapes. V important in areas of California as well as Casablanca, Chile
How does aspect impact on heat?
The direction of a slope with grapes on it effects heat - those facing the equator receive the most heat so in the NH that’s south facing slope and in SH it’s north facing slopes that get the most warmth. This is especially important in cool climates where this can be the difference between ripening or otherwise. Steeper slopes benefit even more e.g. best sites in Mosel Germany which have favourable aspect and are very steep
How do ocean currents impact on heat?
They transport large volumes of warm or cold water across the ocean leading to localised warming or cooling e.g. Humboldt current off Chile cools that region, which might otherwise be too hot for growing and the Gulf Stream warms NW Europe which might otherwise be too cold.
How does altitude impact on heat?
As altitude increases, temps drop which means high altitude regions may be able grow vines despite proximity to the equator.
What latitude do most vineyards fall in and how does it affect heat?
Most vineyards lie between 30 and 50 degrees north and south of the equator. Closer to the equator is too hot and further away is too cold.
How can soil affect heat?
Soils dark in colour or high in stone and rock content absorb and radiate more of the sun’s heat than light soils. This can be critical for ripening fruit in cold climates. Soils with high water content need more energy to warm and conduct heat from the vine more quickly than dry soils - this can delay budburst.
What is continentality? How does it impact on growing?
Temp difference between coldest and hottest months. High continentality = large differences in seasonal temps. Continentality will determine the length of the growing season and impacts the total amount of heat available to a vine, which impacts the grape varieties which can be successfully grown in a region.
How can lakes or seas impact on continentality?
Large bodies of water like lakes heat up and cool down more slowly than land masses so in winter they have a warming effect on the surrounding air and in summer they have a cooling effect. Areas close to these bodies of water therefore generally have low continentality compared to inland regions.
What is diurnal range and how can it impact on the grapes?
The difference between day and night temps. Cool nights slow loss of aromas and acidity during ripening, warm ones accelerate ripening e.g. in a warm region with hot climate a vineyard with large diurnal range can produce wines that are fresher and more aromatic compared to one with small range.
What factors can impact on diurnal range?
Proximity to seas and lakes can reduce diurnal range because they can hold enough warmth to keep adjacent areas warm overnight and provide cool breezes during the day. Cloud cover also impacts diurnal range - temps drop more quickly on clear nights and rise more slowly on cloudy days when sun can’t heat the ground directly.
What are potential hazards to temperature in winter, spring and summer? How can each be potentially combatted?
- Winter
- Too harsh. if temp falls below -20 then the vine can be seriously damaged or killed buy freeze. The graft is at most risk. Earth can be used to cover up and protect the graft = earthing up.
- Too mild. On the other hand, If winter is mild or there is none the vine won’t have a dormant period and may produce more than 1 crop per year = this shortens its life and quality of grapes suffers. Mild winters also mean larger populations of insect pests attack the vine after summer - Spring
- Spring frosts occur when cold air below 0 collects at ground level and freezes water vapour that has settled on the ground or vine. This kills newly burst buds or young shoots. Damage done and impact on yields can be enormous.
- Cold temps in spring delay budburst and shorten the growing season, meaning there isn’t enough time for full ripening in autumn before it gets too cold. Flowering and fruit set can be disrupted resulting in smaller yields. - Summer
- very hot temps can be harmful and prolonged periods of extreme heat slow and eventually stop vine activity which prevents proper ripening.
What can be done to protect against spring frost?
- heaters can be used to prevent the cold air settling, wind machines can be used to draw warm air from above to keep ground from freezing - usually incorporate heaters
- sprinklers may be used to spray water on the vines, as water freezes it releases some heat to the plant tissue protecting the buds
- thoughtful vineyard design can ensure that vineyards are on slopes and avoid any depressions in which cold air collects given cool air settles in lowest points
- vineyards planted in the middle of a slope are at less risk than those in low areas
What is the significance of sunlight for the vine?
It is required for photosynthesis, which keeps plants alive. The more light there is the more a vine will photosynthesise and the more glucose will be produced for growth and ripening of grapes. Flowering and fruit set also benefit from sunlight.
How does latitude impact on sunlight?
Day length during summer is longer the further a site is from the equator, this is important as it provides extra sunlight which helps ripening like for Riesling in Germany.
How does aspect impact on sunlight?
A slope’s aspect affects amount of light it receives and steeper slopes benefit most. Vineyards facing equator receive the most sunlight - the greater the distance from the equator the weaker the sun’s energy so for vineyards closest to the Poles maximising sunlight with good aspect is v important.
How do seas and lakes impact on sunlight?
Sites near large bodies of water experience more cloud cover, those in large land masses tend to be sunnier. However those above rivers or lakes may benefit from light being reflected off the water.
What are the main hazards to sunlight and how can they be managed?
Times when low light levels occur during the year can cause issues - it is needed for flowering and fruit set, so cloudy conditions can result in a smaller crop. The slowing in photosynthesis caused by heavy cloud can stope full ripening. Leaves can be arranged to maximise sunlight access to grapes in tough circumstances.
What is the result of too much sunlight and how can this be managed?
Intense sun can lead to sunburn leading to bitter flavours in the grapes. This can be managed by arranging the leaves to shield from the sun in these circumstances.
What are the different types of irrigation available?
Rainfall irrigation - most important but if insufficient can be supplemented as law permits.
Drip irrigation - most advanced and expensive, each vine has own computer controlled dripper.
Sprinklers - cheaper than drip but waste a lot of water and can create damp conditions increasing risk of disease. Can be used against frost too.
Flood irrigation - only possible if flat or gently sloping site where there is access to lots of water.
