Challenges: Perspectives of Expert Growers

Under-the-Vine and Other Cover Cropping Practices in North Coast Vineyards

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Larkmead Vineyards

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Nabor Camarena manages 110 acres of winegrapes for Larkmead Vineyards in Calistoga (Napa County), which was first established 125 years ago. He began using cover crops widely in the vineyard about 13 years ago as a way to protect the soil and to improve soil health. He recognizes the important role that soil health plays in maintaining vine health and in creating resiliency against climate change. He also sees cover crops as a great way to add organic matter to the soil and to create habitat for pollinators. After many years of trial and error, Nabor was able to establish a permanent cover crop that reseeds itself really well and requires minimal intervention. Nabor recognizes that a healthy permanent cover crop requires constant management throughout the winter, especially during risks of frost damage to the vines, but he is convinced the benefits are real and worth the extra work. Nabor has also been successful in establishing a permanent cover crop under the vine and he has experimented with several tractor attachments that have helped him manage the vegetation effectively with minimal soil disturbance.

 

Robert Sinskey Vineyards

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Kari Flores is the farming operations manager for Robert Sinskey Vineyards in Napa and Sonoma Counties. All of the vineyards are certified organic and are farmed using biodynamic practices, and they have been cover cropped since they were established in the 1990s. While cover crops were originally implemented as a way to reduce soil erosion, other benefits were soon recognized, contributing to the decision to continue with the practice long-term. According to Kari, “Now we are also interested in using cover crops to help us put more carbon in the soil, increase water retention and nitrogen cycling. We also like to provide enough vegetation for bird habitat and for sheep grazing.” They have established a permanent cover crop that has lots of resident vegetation along with self-reseeding triticale, annual rye, and vetch. Kari also maintains a permanent cover crop under the vine composed of volunteer resident vegetation and manages it with an under-vine cultivator and weeder attachment from a French manufacturer, that creates only minimal soil disturbance. The rest of the cover crop in the vineyards is typically terminated via sheep grazing.

 

Tres Sabores

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Julie Johnson is the owner of Tres Sabores Vineyard in St. Helena. Tres Sabores is certified organic and is farmed with no irrigation. As Julie describes it, “we want our operation to incorporate regenerative practices for the overall health of the vineyard. We want good soil structure, and we want our farming to coexist with wild spaces.” Tres Sabores has been using cover crops since 1987 with the goal of enhancing microbial activity, controlling erosion, increasing water holding capacity, and increasing biodiversity. A typical cover crop mix used at Tres Sabores is composed of 40% Cayuse Oats, 30% Bell Beans, 20% Magnus Peas, 10% Lana Vetch, and Daikon radish. In recent years Julie has been tilling in half the cover crop and the other half has been terminated using a roller-crimper. Julie is making an effort to reduce soil disturbance and she is actively looking for cover crop species that can help her achieve that goal. Julie sees lack of rain as the main limiting factor for establishing a healthy cover crop in the winter. “I would like to seed the cover crop just before the first rains come in, hoping there will be sufficient rains the rest of the winter.” Tres Sabores allows the winter crop to grow under the vine and then cultivate it in the spring. According to Julie, the benefits of growing a cover crop under the vine are the same as growing a cover crop everywhere else in the vineyard. “The benefits are the same as in the rest of the vineyard, nitrogen fixation, good soil structure, enhance water holding capacity, carbon storage. The only challenge is to manage the cover crop to terminate it at the right time but we have the equipment to do that successfully.”

 

Seavey Vineyards

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Jim Duane manages 40 acres of winegrapes for Seavey vineyards in St. Helena. This operation has been using cover crops since 1982. Currently, winter cover crops are only seeded on 15 acres of the vineyard because the rest is too steep for seeding, so natural vegetation is allowed to grow there instead. A cover crop mix that has worked well for Jim in the past includes 40% Cayuse oats, 30% Bell Beans, 20% Magnus peas, and 10% Lana vetch. Jim sees cover crops as an opportunity to build soil structure, improve water penetration, and get nutrients into the soil. He is also interested in the potential of cover crops to fix nitrogen and to help with soil compaction. Jim’s main limitations to establishing a healthy winter cover crop are lack of rain and the availability of equipment. “Ideally I would like to seed it earlier in the year to give enough time for germination, but we have not gotten enough rain in past winters. I also need to make sure the equipment is available to do the seeding. Ideally I would like to seed it right before the first rains.” Recently, Jim has terminated all his cover crop by tilling it into the soil. In the future, he would like to move away from tilling and just mow the cover crop but will have to adjust to operating on uneven terrain in the hilltop blocks.