What are the 5 most important things a vine needs to survive?
- Carbon dioxide
Finish this equation:
Sunlight + CO2 + Water = ___ and ___
Glucose and Oxygen
Vines use ___ and ___ to fuel its growth and ripen its grapes.
Glucose and nutrients from the soil
Where does the oxygen go that vines make during photosynthesis?
The vines exhale it through their leaves.
What is the defining factor that determines which grape varieties can grow where?
The amount of heat an area gets during its growing season.
Something to keep in mind: continentality + a region's proximity to bodies of water are tied into this because they help influence the region's total amount of heat during the growing season.
What natural factors affect/influence temperature and heat in a vineyard?
- Ocean Currents
- Soil structure
- Slopes and aspect
- Diurnal range
What 3 factors affect/influence sunlight in a vineyard?
- Bodies of water
What are the optimal latitudes for growing vines around the world?
Between the 30th and 50th latitudes north and south of the Equator.
Put another way, between latitudes 30 and 50 degrees in the northern and southern hemispheres.
Why isn't it possible to cultivate grape vines close to the Equator?
Because areas close to the Equator have annual average temperatures that are far too high which do not allow the vine to go dormant. And if a vine is unable to go dormant, it'll produce less-than-optimal fruit and tire out in only 15-20 years.
Fun Fact: there is one place in Northern Brazil, Vale de São Francisco, that is capable of two harvests per year.
How does altitude affect grape growing?
As altitude increases, temperatures decrease.
Altitude is what allows some regions to exist closer to the Equator, e.g. Cafayate, Argentina which sits ~3,000m above sea level.
What is the effect of the Gulf Stream on Europe?
The Gulf Stream adds a warming effect to the climates of northern and western Europe.
The Gulf Stream originates near the tip of Florida and crosses the Atlantic Ocean.
What is the cold ocean current that affects South Africa?
Name the cold ocean current that affects Chile.
How can fog be beneficial to vineyards?
It can have a cooling effect on vineyards which would otherwise have difficulty growing premium grapes (the vineyards would get hot and stay hot).
How can soil affect a vineyard's temperature?
Rocky, slatey soils - stony or dark in color - absorb heat during the day, and release it overnight.
- Galets roulés in Châteauneuf-du-Pape
- Blue slate in the Mosel
- Llicorella soil in Priorat
Which way do vineyards face in each hemisphere to ensure optimal sun exposure?
Vineyards in both hemispheres will face the Equator for optimal sun exposure.
Northern hemisphere vineyards will face south.
Southern hemisphere vineyards will face north.
What is a diurnal shift?
A diurnal shift is the change in temperature from daytime to nighttime.
The larger the diurnal shift (lower lows, higher highs) the better it is for the vine; warm daytime temps help develop sugar and phenolic ripeness whereas cool nighttime temps help preserve acidity and freshness.
What are 2 things can reduce diurnal range?
- A vineyard's proximity to a body of water
- Cloud cover
Besides decreasing diurnal range, how else does cloud cover affect a vineyard/vines?
Slow flowering and fruit set because the vine isn't getting enough sunlight to photosynthesize, which will ultimately produce a smaller crop;
- Heavy clouds can stop grapes from fully ripening.
What does continentality mean?
Continentality is the difference of temperature between the coldest month and the hottest month in a region.
Regions with high continentality have big temperature differences between their coldest winter months and their hottest summer months.
Regions with low continentality have less of a difference in temperatures throughout the year.
What effects do bodies of water (oceans, lakes, rivers) have on climate?
Bodies of water help moderate temperatures, reducing continentality; meaning, temperatures will hit neither extreme lows nor severe highs.
Vineyards in close proximity to bodies of water have diminished diurnal range as bodies of water emit stored warmth at night (and during the beginning of winter) and supply cool daytime breezes.
Describe lake effect.
As large bodies of water take a long time to warm up and cool down, 'lake effect' has a moderating aspect on climate.
During the autumn, a lake that has warmed up over the summer releases its accumulated warmth to the surrounding land thereby extending the growing season for grapes and keeping away early frosts.
During the spring and early summer, the lake is still cold from winter. As the land around a lake heats up, warm air rises from the earth which sucks in the cool air coming off the lake, creating on-shore breezes.
At what temperature can vines be damaged or killed by a deep winter freeze?
The most susceptible part of a vine to winter freezes is the ___.
Graft (if the vine has been grafted)
What does 'earthing up' mean?
'Earthing up' is when a vicitulturist mounds up additional soil around the base of the vine's trunk as an insulation layer to help retain warmth over winter.
This is done to young vines in particular to protect against deep winter freezes, especially new grafts.
Describe what spring frost is.
What kind of damage can it do?
When cold air (below 0ºC) freezes water vapor hovering at ground level or around the vine.
Frost can kill new shoots and buds that have just burst, impacting yields.
What are the 4 important protections a viticulturist can take against frost?
Heaters and smudge pots which create a blanket of warmth to keep the vineyard from freezing;
Fans, wind machines, or helicopters to circulate warm air above the ground with the cold air that settled around the vines;
Sprinklers, which spray water onto a vineyard so that a thin layer of ice forms on the vine which helps insulate it;
Conscientious vineyard design to avoid depressions; can also high-train vines.
Why do rivers mitigate frost damage?
Because river currents keep air moving - instead of settling - in vineyards.
What can cold springtime temperatures lead to?
Delayed budburst --> shortens growing season
Disrupted flowering/fruit set --> lower yield
What can sustained, extremely high summertime temperatures lead to?