Definition - What does Vigor mean?
Vigor refers to the growth rate of a grapevine. It is affected by many of factors in the environment including, but not limited to the soil, fertilizer, weather conditions, pests, etc. Both high vigor as well as low vigor can be damaging to the wine production process. It is important for vigor to be just right in order to achieve optimum quality grapevines.
WineFrog explains Vigor
The vigor of a grapevine is an important factor that affects the overall quality of the wine. A vine with good vigor has a perfectly balanced ratio of fruit to leaves to canes. However, a vine with high vigor will produce too much fruit, and a vine with low vigor tends to have too much foliage.
High vigor results in a bigger berry size, which in turn weakens the flavor of the wine. Low vigor results in under nourished berries, which completely alters the wine's taste. Vigor must be carefully controlled to produce wines with quality characteristics and balance. Grapevines do not need a lot of water or fertilizer, so a viticulturist must keep that in mind and tend to their vines accordingly.