Building Soil Health at Pennyroyal Farm and Navarro Vineyards

Story by Stephany Wilkes
Photos by Paige Green Photography

In Mendocino County, California, Navarro Vineyards and Pennyroyal Farm have practiced aspects of regenerative agriculture and no-waste farming for so long – soil carbon sequestration, manure production for compost application, solar panels – that it is hard to imagine what more they could do. 

“Oh, we could do so much better,” Sophia Bates says, smiling. “We are always asking ‘What can we fix? As we learn more, I think we’re on the cusp of moving into a new era of soil health. Soil health principles are becoming the foundation of our program.” 

Sophia is the Head Gardener for two operations owned by the Cahn-Bennett family, a somewhat deceptive title given her shepherd role and extensive livestock experience. There is a lot to manage – a goat and sheep dairy, creamery, vineyard, compost, hayfields and, of course, farmstead at Pennyroyal in Boonville, California, as well as the winery operation, gardens, and rangeland at Navarro Vineyards less than ten miles away. Two hundred and twenty ewes – and, depending on the season, their lambs – play a big part in tending and nourishing these landscapes.

“At Navarro Ranch, we have timber, some steep, wooded canyons, and oak savanna over about 900 acres from the ridge to the valley floor. About 500 of those are fenced into varying sized pastures for sheep,” Sophia explains. “The range is where flocks spend much of the year and where we lamb.” There are 90 acres of wine grapes, mostly at low elevation, but some of the Pinot is planted on the hillsides at higher elevations. Pennyroyal is 90 acres with 23 of those planted in grapes. 

Sheep play different roles in vineyards, depending on the goals, context, and available infrastructure and labor to manage them. Some operations may use sheep strictly to graze grass alleys between the vines, for example. At Pennyroyal, sheep play multi-faceted and nuanced roles.

The sheep are a mix of crossbred range types, and Sophia has a “special forces crew” of about 30 Babydoll Southdowns that prune suckers and help manage weeds under the vines during the growing season. Babydoll sheep are short in stature, which leads some people to assume they will automatically work well in vineyards because they are too short to reach the grapes. Babydolls, however, can climb, and are stocky and strong. These factors plus their short height means things like two-wire fence usually do not work for them. 

 

“They have to earn their vineyard grazing privileges,” Sophia says. “And when they do, they get a special ear tag, a green one. These Babydolls – which are only 30 of the total 90, the shortest and the fattest – are our best vineyard grazers. The shorter and fatter they are, the less motivated they are to climb up into the canopy or fruit zone and damage the crop. The suckers detract the vine’s resources from the developing fruit, so the suckering crew goes in after bud break and, ideally, gets the two-to-three inch long suckers off the trunk of the vines when they are still tender shoots. If they don’t eat the whole shoot, it is not as effective and we have to have the vineyard crew come in and prune by hand. That small crew of 30 sheep is managed in small, electonet paddocks within the vineyards, to ensure they are thorough with their work.” 

Sophia explains that the suckering sheep usually follow mowing and discing, because “Having less grass in between the rows means the sheep focus on suckers and undervine weeds, which are harder to manage without herbicides. We will often mow the rows between the vines before sheep come in, which forces them to eat what’s under the vines, and then that is more cleared out for any undervine implement or hand work that has to follow.” 

For cover crop in vineyard alleys, however, it’s the opposite: the sheep take a pass before the tractors go through, often in the wet spring season when tractors would compact the soil, if it were even possible to bring tractors in at all. 

A cover crop is a plant, or a mix of plants, that is used in crop rotation. Soil loves a root and soil loves a cover, and cover crops provide the soil with both. In so doing, cover crops improve the soil, prevent erosion and soil moisture loss, outcompete weeds by growing taller and crowding them out, and add nutrients. Some cover crops are grazed  or crimped, some are cut and become root stubble that is subsequently grazed by animals like sheep, while others are turned into the soil to decompose and provide additional organic matter and nutrients. 

Sophia says, “When we graze a lot of sheep at one time, across small sections, the sheep do a pretty thorough job of taking down cover crop. It comes out looking almost as uniform as from a mower, but depending on the timing of the grazing and the maturity of the cover crop, some mustard and bell-beans stalks will be left standing. These usually get cleaned up by a tractor pass that comes through later on, to chop up the prunings that get left in the rows from the winter. We usually have to make another tractor pass in the late spring to take down the regrowth of cover crop after the grazing, and when the warm season grasses are starting to take off. I’d love to be able to manage it all with sheep, but we’d need a lot more of the vineyard-approved Babydolls for that second pass, since the vines are already growing and full-size sheep would decimate them.”

Though the Pennyroyal sheep are primarily service animals, Sophia herself is a fiber person. “We were approached by Full Circle Wool, which was looking for locally produced fiber. They only buy certified Climate Beneficial wool, so we got together with Fibershed to solidify our Carbon Farm Plan (CFP) and get our Climate Beneficial wool certification.” 

They did, and Pennyroyal and Navarro Vineyards bought finished yarn made of their wool back from Full Circle Wool, to sell in their tasting rooms. “Yarn is one part of some shelf-stable product development we’re doing,” Sophia explains. “Yarn, beans, sheepskins, pickled and canned vegetables, things of that nature.”

The Carbon Farm Plan also has Sophia going deeper on soil considerations, and rethinking their traditional cover crop mixes with Vineyard Manager Natalie Birch. 

Cover crop mixes often provide more benefits than a single cover crop species can. “Our cover crop mix was pretty standard, so we are reexamining that,” Sophia says. “We kind of learned the status quo of cover crops but are thinking of trying new things, like blending multispecies brassica and soil-builder mixes based on vineyard soil profiles, and conducting cover-crop trials with sheep. Gabe Brown is an inspiration there, with a 12-species cover crop mix that, once established, seems to create an even more symbiotic relationship between the plants.” 

Sophia is right. North Dakota rancher and author Gabe Brown has led the regenerative agriculture movement with his own experimentation and demonstrated soil-building results. Brown began planting eight-species mixes, which increased to 10 species, then 12, and today 15-25 species is typical for him. Biodiversity is the goal of these mixes: Research indicates that the more species there are in a cover-crop mix, the healthier the whole stand of cover crops tends to be – especially in trying times like drought. The diversity of complementary plants seems to help one another out, rather than compete. 

Cover crop mixes attract pollinators and a greater variety of beneficial insects (natural pest control), and also seem to mitigate plant disease by suppressing soil pathogens that could more easily tackle a single species.

“Reducing the cover crop height is one of our biggest goals for the sheep in the spring,” Sophia says. “We have the frost factor in our area, so a tall cover crop can actually put the tender buds and shoots of the emerging vines at higher risk for frost damage. The frost settles on the top of the cover crop, and if there is no cover crop, the cold air settles closer to the ground. It will actually be a full degree or two warmer up where the buds are emerging, and that makes the difference in whether or not we have to turn on fans or sprinklers to protect the vines. It’s a juggling act because we don’t want to get in there and graze too early. We don’t want to leave the soil without cover during rain events and in our area, and even cool-season cover crops planted in fall don’t really take off until February and March, when  it warms up a bit and the days are getting longer. Cover crops are most beneficial to the soil at the flowering stage, so we want to leave them as long as possible but get them all grazed before bud break and frost protection season. But in a wet year, it is too wet for tractors to mow before bud break. Fortunately, the sheep can go in and get it done when a tractor can’t, or shouldn’t. With our own flock on site, we can really tailor our timing, though I often wish I had a much bigger flock for about three weeks in early March. We time our breeding so that we have the most animals on site, eating in the months when we have the most grazing work for them, but we still don’t have enough to keep up with the grass. Then it all dries out in June and we sell a bunch of lambs.”

With the support of Fibershed, Pennyroyal is planning a new pollinator hedgerow for fall 2024 and, with a Fibershed Carbon Farm Seed Fund grant is adding some silvopasture planting for the dairy goats – fruitless mulberry trees. “Goats love mulberry leaves,” Sophia says. “The trees grow really quickly, so they will provide shade for the goats and cool the area outside of their barn.” For fire safety, the mulberry trees could not be planted directly beside the barn, which would have helped cool the structure even more. 

“These days, It’s such a balance between dealing with rising temperatures and reducing fire risk,” Sophia says. “And there is always more we could be doing.”