Grapevines need full sun, about 7 to 8 hours daily, for abundant fruit. Less light leads to lower fruit production and quality. Grapevines will grow on many soil types, but drainage is important.
Some grape varieties thrive with a balance of sun and shade, needing about 6 hours of direct sunlight and tolerating some periods of partial shade without compromising growth or fruit quality. This allows growing these grapes in slightly cooler regions with more temperature changes.
Grapevines require 1,400 hours of sunshine to ripen. Warmer climates produce riper, richer fruit, while colder climates or those at higher elevations tend to produce crisper, more tart fruit. Sugars produced during ripening lend sweetness to the grapes. Excessive heat can cause heaviness in the fruit. Vines need enough heat to ripen the grapes effectively, yet temperatures below 10°C and above 35°C disrupt photosynthesis, inhibiting growth.