The Scoop on Compost: Turning Vineyard Waste into Black Gold

​Now we’re talking about black gold! Composting is a vineyard practice that has grown in popularity from Carneros to Calistoga, and for good reason—it’s a sustainable way to give back to the soil and support a healthy vineyard ecosystem. Rich in organic matter and teeming with microbes, compost boosts soil health by encouraging microbial activity and improving the structure and fertility of the soil.

​In Napa Valley, spent grape skins and seeds—called pomace—are often recycled into compost after being pressed at the winery. Some vintners even make their compost onsite and return it to their vineyards in the fall, creating a perfect farm-to-farm cycle. Compost can be spread across the entire vineyard floor or applied directly beneath the vine rows, depending on the vineyard’s needs.

Many vineyards follow a composting rotation, applying about 5 tons per acre every three years. However, struggling blocks or soil needing extra attention might see compost applied more frequently or at higher rates to give it a boost.

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Cow and sheep manure is a valuable addition to compost, adding nitrogen and other nutrients that fuel the composting process. Photo by Sarah Anne Risk

​​You might have also heard of compost tea—a liquid version of compost created by steeping it in water with added oxygen for about 24 hours. The result is a microbe-rich liquid that can be added to drip irrigation systems throughout the year, providing a steady dose of beneficial microbes to the soil and vines.

Want to dive deeper into the science behind compost? Dr. Elaine Ingham, a renowned soil microbiologist, has dedicated her career to understanding the soil food web and its importance in healthy farming practices. Check out her website at soilfoodweb.com for tips, methods, and everything you need to know about composting.
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From boosting soil fertility to reducing waste, compost truly is the black gold of Napa Valley vineyards—and it’s a shining example of how sustainable practices can support world-class grape growing. 🌱🍇

Learning about compost from Yount Mill Vineyards at the 2024 Organic Winegrowing Conference.