Can A Vine Take the heat?

Every summer in Napa Valley, the same question finds its way into conversation.

Can grapevines thrive in extreme heat?

The answer is nuanced.

Vines are remarkably resilient. They have evolved sophisticated mechanisms to protect themselves during periods of high temperatures, but like any living organism, there is a point where survival takes priority over growth.

This past week, temperatures climbed well into the 90s and low 100s across Napa Valley. Even mountain vineyards experienced significant warmth, reminding us that no two growing seasons are ever alike.

Nature Knows What to Do

When temperatures become excessive, grapevines begin to conserve energy.

Tiny pores on the leaves, called stomata, partially close to reduce water loss through transpiration. As a result, photosynthesis slows during the hottest part of the day. Rather than continuing active growth, the vine shifts its focus toward protecting itself until temperatures become more favorable.

To the casual observer, it may seem as though the vineyard has paused.

In reality, the vine is making an intelligent decision.

As evening temperatures cool, photosynthesis resumes, and the vineyard continues its quiet work.

Spring Mountain: Elevation Meets Resilience

Our estate vineyards on Spring Mountain benefit from elevation, varied aspects, and volcanic soils that naturally limit vigor and encourage concentration.

While warm afternoons are part of every Napa summer, the mountain's changing elevations, forest canopy, and varied exposures create a mosaic of microclimates. Individual vineyard blocks can experience different temperatures and sunlight throughout the day, requiring careful observation rather than a one-size-fits-all approach.

During periods of elevated temperatures, our vineyard team focuses on preserving healthy canopies that naturally shade fruit, monitoring vine water status, and allowing the vines to respond as nature intended.

Great farming is rarely about intervention.

More often, it is about understanding when not to intervene.

Down Valley: Our Mount Veeder Vineyard

Our One Lane Bridge Vineyard on Mount Veeder tells a different story.

Although this week has brought warm conditions there as well, Mount Veeder is heavily influenced by cooling marine air moving inland from San Pablo Bay. The appellation is typically cooler than much of the Napa Valley floor, often by 10–20°F during summer afternoons, resulting in a longer growing season and one of the latest harvests in Napa Valley.

Its ancient marine soils and persistent afternoon breezes encourage naturally small berries with exceptional concentration, while the slower pace of ripening helps preserve freshness and structure.

Though both vineyards are unmistakable, each expresses its own rhythm.

Spring Mountain and Mount Veeder are separated by only a handful of miles, yet each offers a distinct conversation between climate, soil, elevation, and vine.

The Beauty of Mountain Viticulture

Heat is only one chapter in a growing season.

The character of a wine is ultimately shaped by the accumulation of countless days and nights, warm afternoons balanced by cool evenings, periods of rapid growth followed by quiet pauses, and the steady work of both nature and those who farm the land.

As our 2025 wines continue their patient evolution in barrel, another vintage is unfolding outside beneath the summer sun.

One vintage is finding its voice in the cellar.

The next is finding it in the vineyard.

Stay Tuned.