Unraveling Growth Degree Days for Viticulture

As winter recedes, we witness a miraculous transformation in our vineyards. New buds break free from their winter sleep, unfurling into vibrant leaves. These are soon followed by beautiful inflorescences and delicate flowers. As the season advances, these flowers give way to fruits that grow and mature with time.

For grapevine growers, each stage of plant development is crucial, dictating the course of their farming activities. Understanding when a plant will reach a particular developmental stage is invaluable, allowing farmers to plan their activities accordingly.

While plants tend to reach specific stages around the same time each year, it does not occur at the same time of year. Often, there can be a variation of more than two weeks. Moreover, different grapevine varieties reach these stages at different times, influenced by their unique genetic makeup.

It's clear that plants sense external environmental conditions and break their dormancy to initiate growth stages. But how exactly does a plant sense its environment and decide to break dormancy? And can we predict when a plant will reach a particular growth stage?

Amerine and Winkler (1944) were the first to hypothesize a correlation between a plant's developmental stage and cumulative temperature in viticulture, assuming adequate water and solar radiation availability. Since then many models have been developed to address specific conditions.

If you're intrigued and want to learn more about Growth Degree Days, stay tuned for our upcoming blog. We'll explain how to leverage this information for effective grapevine management. Your journey into the intricate world of grapevine growth is just beginning!