Viticulturists (like myself) are concerned with three levels of climatic effects on the grapes:
- Macroclimate (regional climate of an area in Indiana)
- Mesoclimate (the climate of a specific site – we have several within the Dulcius acres)
- Microclimate (the climate in and around the vine canopy)
Climate depends on a large number of factors such as sunlight, rainfall, temperature, temperature swings, etc. One part of determining our mesoclimate is collecting data which are used to calculate "Growing Degree Days," a measure of the amount of heat available to grow and mature the grapes, to bring an insect out of dormancy, or to develop a particular fungus.
Most grapes will not grow below 50°F so we don’t want to count the times that we were below 50°F and grape growth stops by 120°F. Temperature changes all through the day and that information is collected by our Crane Lake weather station. That information is sent to GRASSLinks a web-based interface to a geographic information system (GIS), which offers public access to mapped information. Our very own Crane Lake weather station (photo, below left) provides data to Oregon University where it is used to determine growing degree days.
6 days ahead of 2016
12 days ahead of a 30 year average
Results of this increased amount of heat are:
- Grapes budded out earlier and were damaged by a late freeze.
- We began spraying for fungus and phylloxera earlier.
- Harvest may come earlier this year.