Robert Hall Winery Has A Regenerative Viticulture Field Day

Robert Hall Winery in Paso Robles has begun a three-year study of regenerative viticulture on a 40-acre block of estate vineyards adjacent to the winery along Highway 46. If the study is successful, regenerative viticultural practices will be applied to the entire 125-acre estate vineyard and potentially to other O’Neill Vintner & Distillers properties.

It isn’t unusual for companies to undertake trials to evaluate farming or other practices, but inviting the public along to witness the process is. The project launched in November 2020 and in early March 2021 Robert Hall Winery held the second field day in the vineyard to introduce the public to regenerative viticulture using biodynamic practices. In subsequent field days you can follow the progress in the vineyard throughout the seasons.

What is regenerative viticulture? Robert Hall Winery offers this definition:

“The rehabilitation of land through organic & biodynamic farming techniques focusing on restoring soil health & increasing organic matter which enables carbon sequestration.”

Robert Hall Winery is certified sustainable by California Sustainable Winegrowing Alliance and the estate vineyard is farmed sustainably. Sustainable farming practices allow the application of conventional herbicides, pesticides and fungicides; regenerative viticulture does not.

During the March field day Caine Thompson, Robert Hall Winery Managing Director, and Philippe Armenier, noted Biodynamic Consultant, outlined the differences between the two types of farming and the steps that will be taken to transition to a regenerative way of farming.

Caine Thompson (L) and Philippe Armenier (R) photo
Caine Thompson (L) and Philippe Armenier (R)

Philippe Armenier has experience both as a biodynamic farmer and winemaker. Some thirty years ago he was the first in Chateauneuf-du-Pape to make the transition when he converted Domaine de Marcoux, his family’s vineyard and winery, to biodynamic practices. Since then he has become a respected biodynamic consultant around the world and will facilitate the regenerative farming study at Robert Hall.

Caine learned to farm organically as Company Viticulturist with Mission Estate Winery in New Zealand for 8 years. He built on that knowledge during his 4 years at Pyramid Valley as Managing Director where they farmed biodynamically while practicing regenerative farming. He and Philippe first met at a conference in New Zealand.

“This type of farming takes us in a completely different direction, which we’re really excited about,” Caine told our group of wine enthusiasts and winery staff.

The First Steps

Learning to farm in a new way will eliminate herbicides and pesticides immediately. The first steps in the vineyard began by adding organic compost and tilling between the rows to loosen the compacted soil. Compacted soil doesn’t hold much oxygen, which is an essential quality for healthy soil. Soil organisms rely on it and a breathing soil allows the vines to achieve harmony by taking up soil nutrients. And tilling under the vines has replaced the spraying of herbicides to control weeds. 

Regenerative viticulture test block photo
Regenerative viticulture test block

The first biodynamic preparation (a compost tea made with a small amount of barrel compost) was sprayed on the soil in January and several times since. Barrel compost (made with manure, crushed eggshells and basalt) is even more effective at oxygenating the soil than tilling.

Biodynamic preparation 500 (once again a tea is made using a small amount of cow horn manure) will be sprayed just after bud break to further enhance root development – to strengthen the vines’ connection to the earth. Later, the canopy will be sprayed with a silica (quartz) preparation to bring nutrients to the vines and enhance growth above ground – to strengthen the vines’ connection to the cosmos.

All work in the vineyard, including picking decisions, will be completed according to the biodynamic calendar, which takes into account the movement of the moon, planets and constellations. Philippe told us the moon has a power (pull) over all liquids on earth including the seas, sap in the vines and wines in the tank. And the moon impacts fungi as well. Fungi in the soil are beneficial, but when they rise to the vine they are not. When this happens in the vineyard, the viticulturist must look for the reasons why and solve the problem. When work in the vineyard cannot be completed strictly according to the biodynamic calendar compensation on other beneficial days will be made. A farmer must be practical.

Friable, moist soil between the vines photo
Friable, moist soil between the vines

The first year of transition will cleanse the vineyard from past farming practices and establish harmony. The second year should begin to show visible change in the vineyard. Philippe did note that some small changes in the soil are already evident. Before the project began he struggled to get a shovel into the heavily compacted soil. He is now able to easily put a shovel into the soil and it easily falls off the shovel. During recent rains the test block suffered only minimal erosion due to runoff meaning more of the rain was able to penetrate the soil, which is particularly important in an environment as dry as this part of Paso Robles.

More compact soil under the vine row photo
More compact soil under the vine row

Philippe took a second shovel of dirt from under a vine row. The soil held together more cohesively, more like the soil before the test began. Eventually, the soil under the vines will become as friable as that between the rows. One indication of that change will be lengthening of the root structure of small plants in the vineyard. The same increase in the vines’ root mass and length will occur, strengthening the vines and improving grape quality.

It will take time, especially in so arid an environment, to build humus in the soil and for the number of earthworms to increase, but already there is an improvement in water retention. Philippe told us it takes four years for soils to become biodynamic, but the vines will respond faster to biodynamic practices and he expects big changes by year three. He also noted that older vines respond faster to biodynamic farming than younger vines.

Philippe told an interesting story to illustrate how close to the earth farming used to be and how it include farm animals before large-scale farming became the norm. Back in the day, he told us, one gauge of a farmer’s wealth was the size of his manure or compost pile. We might giggle at the use of manure and compost in biodynamic practices, and roll our eyes at talk of the moon’s cycles, but Philippe assured us both were completely natural in the old way of farming. “We’ve lost that,” Philippe mused. But he is not deterred because he knows biodynamic practices put the farmer, and farm animals through the application of biodynamic preparations, back in the farm.

The Challenges 

Weed control without using herbicides will be a major challenge. A new mechanical tiller is being used for under-vine tilling to control weeds.

The dry Paso Robles environment will be a challenge to increasing organic matter in the soil. But, “a good farmer adapts,” Philippe told us. Farming practices must be unique to the site.

Learning the biodynamic calendar and learning about the various biodynamic preparations and readying them for application will be a continual process. At the present time the biodynamic preparations are purchased from a biodynamic producer rather than being made at the winery. Philippe stressed that organization is essential to successful biodynamic farming.

Collecting Data

Throughout the process Caine will be watching costs and comparing them to conventionally farmed blocks. He is confident the cost structure can be maintained on a relatively small scale, but wants to find out if it will work on a larger scale. He will evaluate expanding the project to other blocks and potentially within the O’Neill portfolio. 

The team will collect data on soil quality, absorbed carbon, yield and quality of the grapes in the test block and compare them to conventionally farmed blocks. Can you imagine how excited the team will be to watch for bud break, flowering, fruit set, verasion and then to taste the first grapes from this first vintage? At some point small lots of wine will be made from the test block to gather more data. 

The Potential Benefits

This part of Paso Robles is very dry, hence the lack of cover crop and drip irrigation in the vineyard in March. If the moisture holding capacity of the soil can be improved then water use should decrease.

The 2020 vintage suffered through hot temperatures in fall that resulted in a decreased yield in this vineyard. It will be interesting to see how the test block performs during subsequent hot spells with the changes in farming.

Caine is obviously excited about the project. He knows from experience how successful regenerative viticultural practices are. And he is thrilled that Jeff O’Neill, CEO of O’Neill Vintner & Distillers, which purchased Robert Hall Winery in 2016, also sees the potential of regenerative viticulture at Robert Hall and beyond. Caine is part of the Executive Team that leads sustainability for O’Neill Vintner & Distillers and the team will be watching the study with interest.

The test block of Cabernet Sauvignon is the source of Robert Hall’s Cabernet Sauvignon that retails for $20. Nothing would please Caine more than to be able to introduce Robert Hall’s customers to their wines with a $20 Cabernet Sauvignon made in a completely transparent way, reflective of the site, using grapes grown without pesticides or herbicides.

Watch the Robert Hall Winery website for an announcement of the next Field Day in Regenerative Viticulture or check them out on Facebook or Instagram. The interactive presentation I attended was free and lasted about an hour. Many of the other attendees enjoyed a wine tasting in Robert Hall’s beautiful outdoor tasting area afterward. That sounds like a good idea to me.

Featured photo provided by Robert Hall Winery.



  1. Regenerative farming looks like the next wave of sustainability. Fascinating stuff. Jason Haas of Tablas Creek discussed their journey on the Bedrock Conversations podcast with Morgan Twain-Peterson, MW recently. I think it’s worth a listen.