Irrigation Best Practices

With changing climate patterns and growing pressure on water resources, precision irrigation is more critical than ever for sustainable winegrowing in Napa Valley. While the decision of when and how much to irrigate should always be site-specific, current tools and knowledge enable growers to make informed, data-driven decisions.
Here are NVG's best practices for efficient, sustainable vineyard irrigation in Napa County.

1. Pre-Season Irrigation Prep
Ensure your system is fully functional and efficient before the season begins:

• Inspect infrastructure: Clean filters, flush lines, and check for leaks or damaged emitters.
• Quantify system output: Use a graduated cylinder to confirm emitter uniformity and compare usage to meter data.
• Monitor your well: Record static water depth at the start and end of the season to detect changes in aquifer levels.
• Adapt to vine variability: Adjust spaghetti tubing based on vine vigor and consider adding a second irrigation line for weaker blocks.
• Test your water: Conduct lab analysis for salinity, pH, bicarbonates, and toxic ions to ensure irrigation suitability.

2. In-Season Maintenance & Monitoring
​Consistent attention during the growing season ensures healthy vines and water efficiency:

• Check and clean emitters and filters regularly.
• Ensure uniform pressure throughout the system to avoid over- or under-watering.
• Use tools, not guesswork, to inform irrigation timing.

3. Tools for Assessing Vine Water Status
Choosing the right tools can make the difference between reactive and proactive irrigation:
Pressure Chamber (Pressure Bomb)

• Gold standard for measuring vine water stress.
• Best when used for pre-dawn or stem water potential measurements.
• Requires expertise to interpret in relation to temperature and vapor pressure deficit.

Plant-Based Sensors (e.g., Sap Flow)

• Real-time data on vine water use.
• Becoming more affordable and scalable.
• Useful for integrating into decision-support platforms.

Soil Moisture Probes

• Effective when installed at multiple depths to capture root-zone variability.
• Pair with plant stress indicators for a complete picture.

Remote Sensing Tools

• Satellite, drone, and in-canopy sensors offer spatial insight into vineyard variability.
• NDVI and thermal imaging can identify stressed zones quickly.

Visual Cues

• Use early-morning observation to avoid misreading transient stress.
• Combine with quantitative tools to avoid over-irrigation.

4. Post-Season Maintenance

• Flush the system to remove mineral and organic buildup.
• Check well depth again to evaluate seasonal drawdown.
• Drain lines and open valves in frost-prone areas to prevent damage.

5. Sustainable Irrigation Matters
Irrigation isn't just about crop yield—it's about stewardship. By refining irrigation practices, growers can:

• Reduce water waste
• Protect aquifer health
• Minimize disease pressure
• Improve fruit quality through optimal vine stress