Practical Winery
58-D Paul Drive, San Rafael, CA 94903-2054
phone:415/479-5819 · fax:415/492-9325
This article is from the May/June 2006 issue of Practical Winery & Vineyard Magazine. Order current or back issues here.


BY Jack Heeger

Chateau Montelena (Calistoga, Napa Valley) has gained a reputation over the past three decades as a producer of high quality wines, particularly Cabernet Sauvignon. Dave Vella, vineyard manager, tends nearly 200 acres of vineyards and credits the high quality to vineyard location.

“The estate vineyards are located in a special place, where the soils and climate and slope have come together to create the perfect spot to grow Cabernet Sauvignon,” Vella explains. “Our location makes growing great fruit easy.”

Other factors also contribute to Chateau Montelena’s success, especially some very careful sustainable vineyard practices that have played a major role in taking advantage of everything the winery’s seven vineyard locations offer.

About two-thirds of Chateau Montelena’s approximately 32,000 annual case production is Cabernet Sauvignon; most of the remainder is Chardonnay, with a small amount of Zinfandel and Mendocino County Riesling.

The Estate Vineyard is the Montelena’s largest (about 115 acres). Eighty-three acres are planted to Cabernet Sauvignon, nearly 20 to Zinfandel and Primitivo, and the remainder to Merlot and Cabernet Franc, which are blended into the winery’s Napa Valley Cabernet Sauvignon.

Other vineyards surrounding the estate include Vella’s personal 12.5 acres planted to Cabernet Sauvignon; Barberis, with 28 acres of Cabernet Sauvignon and Merlot; Montelena Blossom Creek (15 acres) and Montelena Garnet Creek (six acres), both planted to Cabernet Sauvignon, and Wolleson, an eight-acre vineyard just south of Calistoga planted to Cabernet Sauvignon.

In addition, Chateau Montelena leases a 55-acre vineyard in the Oak Knoll District at the base of Mt. Veeder near Dry Creek Road, where mostly Chardonnay grapes are grown.

Vella supervises all the owned and leased vineyards, including Oak Knoll, but the hands-on manager at Oak Knoll is Bill Hanna, who planted the vineyard for owner Frank Takahashi.

Hanna owns and manages a neighboring vineyard from which Chateau Montelena sources Chardonnay. Hanna’s vineyard produced about half of the Chardonnay bottling that was rated tops in the famed 1976 Paris tasting.

Vella is assisted at the Napa Valley properties by four full-time employees, all of whom have been with Montelena for 17 years or longer.

Chateau Montelena produces about 1,500 cases of Riesling from purchased grapes grown in Potter Valley.

Yield at Montelena’s vineyards is generally between one and two tons per acre for Cabernet Sauvignon (planted in the 1970s), Cabernet Franc, and Primitivo/Zinfandel. Merlot vines are more closely spaced and can yield three to four tons per acre.

Vineyard soil
The estate vineyard has Bale, Cole, and Kid series soils that were formed from alluvial and sedimentary parent materials in the lower elevation vineyards and Cortina and Pleasanton series soils that were formed in volcanic parent materials, such as rhyolite in hillside vineyards.

Montelena’s vineyards elsewhere in the Calistoga district are all located adjacent to tributaries of the Napa River and most have alluvial soil, with cobbly, gravelly subsoil, allowing deep root penetration and good drainage with medium (highly variable) water-holding capacity, resulting in moderate vigor.

Six acres of estate Cabernet Sauvignon are planted on Bale and Cole series that are sedimentary soils with a high percentage of clay, producing more vigor, and hillside blocks at upper elevations are planted on rocky, well-drained volcanic soil.

Chardonnay vineyards in Oak Knoll are planted in Haire-loam soil, which contains considerable sedimentary material, such as decomposed shale and blue/gray clay, with moderate drainage.

From his start in 1985, Vella had been maintaining the vineyard soils with annual applications of chicken manure and compost. Feeling that he needed a better balance, Vella set about to enhance the vineyard soils.

“In college, in soils class, you learn that if you’re looking at this type of soil then you add this nutrient,” Vella says. “But that’s not how it really works.”

One day Vella attended a meeting at which Bob Shaffer, an agronomist with Soil Culture Consulting, spoke. As Shaffer addressed the group, Vella thought, “He’s talking about exactly what I’m experiencing.” Chateau Montelena hired Shaffer as a consultant in 1994, and he has been working with the winery ever since, making soil health improvements.

“We’ve done it in small increments,” Vella explains, in deference to his concern for making mistakes by changing things too fast.

For example, with low fertility soil, he asks himself, “What did weed growth patterns look like before the vineyard was planted and vine growth began?”

“Weeds are plants growing on soils with mineral balance and cultural practices that limit more favorable species from growing,” explains Shaffer. “Each plant has an ecological niche where they are most successful. Soils with excess nitrogen, poor structure, and low soil organic matter content are conducive to coarse weeds like star thistle, little mallow, and marestail, for example.

“The balance of soil minerals, especially nitrate nitrogen, calcium, and magnesium, and cultural practices largely determines the species and density of resident vegetation in a vineyard. Systematic selection and management of cover crops, in conjunction with developing good soil mineral balance and developing soil organic matter, is the most effective and economical form of weed management for a vineyard.”

Vella did soil analyses and took tissue samples, but he says, “My biggest fear was changing something that was working, so we went into soil enhancement very cautiously.”

But Shaffer, who took the first soil sample at Montelena in 1994 and began work “in earnest” in 1999, says winery staff has been “very supportive in making changes. I respect Chateau Montelena personnel for what they’re willing to learn and for their desire to build a program for soil health over time, that acknowledges the existing cultural practices.”

A soil analysis is done every year on samples taken from three to ten acres maximum in each vineyard. Shaffer’s first soil analysis revealed that winery soils are part of the Pleasanton and Bale soil series, “and I was already familiar with those soils series,” Shaffer recalls. “I knew the estate soils would greatly benefit from improved mineral balance and elevating the soil organic matter level even though these two series of soils are very different in texture.

“The balancing of minerals and introduction of more organic matter into the soil are synergistic with each other and create elevated levels of soil health that provide many substantial benefits to vines such as improved fruit quality and prevention of diseases.”

Addition of minerals, nutrients, and organic matter to Chateau Montelena’s vineyards began in 1999 with soil application of mined minerals, such as rock phosphate, potassium sulfate, calcium carbonate, and calcium sulfate, as high-quality sources of slow-release minerals.

Quantities are determined by soil analyses, which should be conducted annually because the quantities of minerals used will differ from year to year. For example, Shaffer notes that boron and sulfur must be applied more frequently because they are easily leached.

“Minerals are applied whenever it’s convenient and fits into the work schedule before the rainy season,” adds Shaffer. “It takes rain to make them work and become available in the soil.”

Cover crops
A cover crop was seeded in 2001 at Chateau Montelena, with crimson clover and barley in lower elevation vineyards and rose clover and zorro fescue on hillsides. “It was beautiful,” notes Shaffer, “but it also added to the soil.

“Each year since 2001, we have rotated and diversified the cover crop species to include both annuals and perennials including clovers, grains, California native grasses, European grasses, herbs, and flowers. We select and cultivate cover crops for soil health features such as erosion prevention, increasing soil organic matter, water holding capacity and infiltration, and elevating soil food web functions.

“Additionally, we have employed cover crops to act as a habitat and food resource for beneficial life in the vineyards such as predator or parasitic arthropods, insectivorous birds, and beneficial vertebrates like weasels and foxes. Culturing a diversity of plants with good strategic placement within the vineyards and which can provide pollen, nectar, and habitat over the grape cropping cycle is the goal of beneficial insectary plantings.

“Plants like alyssum, buckwheat, carrot, crimson clover, common vetch, and yarrow, in addition to many resident grasses, wildflowers, and forbs are great choices to cultivate in a vineyard for supporting beneficial life and decreasing pests. There was a clearly noticeable increase in the estate vineyard’s populations of green lacewings, brown lacewings, six spotted thrips, and other generalist predators of vine pests where blooming plants were maintained.

“By using select species of some plants, such as crimson clover, we found that cover crops could encourage tremendous levels of beneficial green and brown lacewings,” Shaffer adds.

The goal for planting cover crop is two-fold: to benefit everything above ground — prevent soil erosion, encourage beneficial life forms, prevent dust, and improve vineyard appearance — and to enhance everything below ground, including better water infiltration. This allows minerals to be transformed into plant-available forms.

Shaffer adds that both beneficial life (predators) and pests (prey) are dependent on prefixed carbon as their sole dietary energy source.

“The trick is to develop a cover crop system in vineyards that tolerates low populations of prey that acts to sustain large populations of healthy beneficial predator organisms throughout the cropping cycle. This way, the cover crop is not only a critical component of soil erosion prevention, soil health, vine health, and fruit quality development, but is also an active component of above-ground pest damage prevention.”

In addition to the carbon in living plant tissues, pollen and nectar are alternative sources of food for beneficial predators, and some cover crops offer more benefit than others. Examples are plants with long bloom cycles, such as alyssum, that support predators over the entire summer and winter, and plants with extra floral nectar sites, such as common vetch and bell beans, which offer large, easily accessible volumes of nectar.

Shaffer recommends maintaining various species of grasses and other plants that bloom at different times to provide continuous, overlapping, and diverse food for beneficial life in vineyards.

“Below-ground cover crops are the most practical means to increase the soil’s available carbon content, which is the sole energy source for the living microbial biomass. The soil’s living microbial biomass provides both biological and chemiophysical advantages to vines growing in soils with plant-parasitic nematodes.

“Cover crops deposit carbon into soils by their root’s exudation and by organic matter when the roots die. North coast soils are generally seriously carbon-limited and without adequate annual return of organic matter, these soils can become disease-conductive. Soil carbon is the sole energy source for the beneficial bacteria, fungi, and nematodes that act to control plant-parasitic nematodes.

“With synthesis of organic matter by plants and the carbon it contains, cover crops provide the most economical, practical, and effective energy source for the living microbial biomass that directly benefit grapevines with the seven essential functions performed by soil food web activity. Other non-living fractions of the soil, such as minerals, humic materials, and non-humic materials are also important sources of nutrition for the live biomass and soil food web functions in soil.

“Selection of cover crop species, used in conjunction with mineral balance and compost, can also act to decrease the negative impacts of plant-parasitic nematodes such as Dagger and Rootknot nematode in vineyards. Cover crop species can be selected to be either non-host or directly toxic to plant-parasitic nematodes. Non-host species are those that do not suit the plant-parasitic nematode’s diet requirements, and therefore weakens them.

“Cruciferous plants, such as white mustard, contain glucosinolates that, upon decomposition in the soil, release isothiocyanate that can lower the population of plant-parasitic nematodes, weed seeds, and fungal pathogens.”

“Our goal in composting is foremost to recycle winery by-products and, upon application, to increase the vineyard’s soil heath,” says Shaffer. “The feedstock, processing, and curing are intended to create a compost that has disease-suppressive character. Windrow and static pile techniques are employed, with plenty of woody materials which feeds fungi in the compost and has a fairly coarse texture, allowing for good air circulation and high populations of beneficial microbes in general.

“We know that, by biological analysis, the estate soils would benefit greatly by higher populations of diverse species of fungi. The compost is intended to inoculate the soil with fungi and to feed all the soil’s macro- and micro-organisms, which then feeds the vine the best possible forms of nutrition.”

A typical compost pile at Chateau Montelena contains about 65% pomace, about 10% chicken manure, 20% woody materials (such as wood chips and wood shavings from barrels), and about 5% compost from the previous pile to act as a starter.

“Fresh water plants from Jade Lake on the estate are harvested from time to time and added — that’s a good inoculant,” Shaffer says. “These water plants simply are another source of diversity, and a recycled material.”

Soil amendments including rock powders such as calcium phosphate, basalt or calcium carbonate are also excellent compost feedstocks.

“There are four groups of functional living organisms (bacteria, fungi, nematodes, and protozoa) referred to as the ‘living microbial biomass’ in soil that provide seven critical benefits that are unavailable from any other means,” says Shaffer. “Well-made and fully-cured compost increases the health of the living microbial biomass and benefits vines in seven ways that are critical for vine health.”

Mineral balance
“For best grapevine growth, we want minerals in soil to be balanced, which refers to both the ratio of the major cations and anions to each other in soils, and also the overall poundage of all essential minerals in soil. Managing mineral balance requires the use of wet chemistry soil analysis to determine the relative balance that currently exists, and improves the predictable outcome of soil inputs.

“Mineral balance and the living microbial biomass in soils controls the pH, rate of mineralization, organic matter decomposition, soil structure, vine health, and significantly affects the quality of fruit production. Soil minerals vary greatly in content in soils due to parent materials, farming practices, leaching or fixation. Soil mineral balance is generally better near the surface of the soil and is less desirable deeper in soil.

“For example, the alluvium and sedimentary soil at the estate are high in potassium due to decomposition of a potassium-rich volcanic rock called Rhyolite that formed from post shield stage lava from Mt. St. Helena. Grapevines and fruit require good potassium availability for their best quality and Chateau Montelena soils provide luxury amounts of potassium.

“However, potassium is antagonistic to calcium, boron, and manganese that are also required for high-quality grapes. By measuring the soil’s mineral balance, we can predict the right amounts of calcium, boron, and manganese required to ‘balance’ the high potassium. Here again, soil organic matter plays a critical role in buffering the negative effects of an excessive mineral and by chelating minerals into forms that are most usable by grapevines.

“Minerals in the soil have antagonistic effects on each other. Minerals in soils do not exist in a vacuum and are subject to chemical and biological forces that either increase or decrease their availability to plant roots. By following scientific guidelines to ‘balance’ the essential soil minerals, vines produce a higher degree of fruit quality and elevated disease resistance or tolerance.”

Soil life
Cover crops, compost, and mineral balance act synergistically to elevate soil health, which support healthy earthworm populations. Earthworms are indicator species of soil health.

Soil treatments have increased earthworm activity in the soil at Chateau Montelena. “We try to delay any required spring tillage until the earthworms have moved deep into the soil as they follow the moisture downward,” Shaffer explains.

Benefits of earthworms, the largest animal in the soil system, are profound, notes Shaffer. “They accelerate decomposition of organic matter, and they make holes deep in the soil, creating a path for water and air.” Earthworms improve soil structure, consume plant-parasitic nematodes, and they change minerals into forms more effective for root uptake.

“The more you learn about earthworms, the more you protect them,” Shaffer declares.

Earthworms are an important component in our effort to limit mechanical tillage — because the earthworms actually are tillers. “They work 24 hours a day, seven days a week with only the cost of some cover crop residues and good mineral balance,” he concludes.

Grapevine selections

Vella reports that 16 different blocks of Cabernet Sauvignon are planted at Chateau Montelena, and because of low vine vigor, the grapes produce an earthy, deep, dark-colored wine. Six acres planted on heavy clay, sedimentary soil have more vigor and the vines yield about 20% more fruit than the rest of the block. Vella notes that the wines produced from these vines are more typical of Napa Valley wine. Hillside blocks on the volcanic, rocky and well-drained soils of the higher elevations of the Chateau Montelena property produce a low-yield but intensely concentrated fruit.

The majority of the Montelena vines are more than 30 years old, and although the trend when they were planted was to use AXR-1 rootstock, the winery chose St. George, and did not experience a phylloxera problem. In 2002 and 2003, 10 acres of Chardonnay in Oak Knoll were replanted with 101-14 rootstock and Clone 4 and 17 scion-wood. At the Home Ranch in 2001 and 2003, eight acres were replanted with 110-R rootstock and clone 337 Cabernet Sauvignon.

The winery has nearly 63,000 vines, ranging from 454 to 906 vines per acre. Eighty percent of them are from the original planting (early 1970s).

Vineyards were originally planted 12x8, typical for 30 years ago, but replanting is 8x6, mostly on vertical trellising. Montelena has vertical, lyre, and two-wire trellising, depending on location, soil type, and varietal.

There is one six-acre block in the Montelena Estate Vineyard where Vella could not control the canopy properly, resulting in poor quality grapes, that has been converted to a lyre system and now “the grapes make the cut every year.”

Extensive leaf removal is done on head-trained vines to open up the center, but not much de-leafing on the canes. Leaves are removed after bloom, again when the berries are pea-size, and one more time around veraison. “If it’s cool or we have a late rain, we’ll do another pass on the Zinfandel and Primitivo,” adds Vella.

Leaves are pulled from all sides. “We’ve had more burn on the morning side than on the afternoon side,” he notes. “But every vine is different.”

Vella does cane pruning because it removes more wood and reduces potential Eutypa and Pierce’s disease. “Our 30-year-old vines are more susceptible to Eutypa,” he says. “We prune as late as possible — we start the latter half of December. We wait as late as we can.”

There’s no specific formula for pruning. The crew looks at each vine individually and prunes to an average of 1 1/2 to 1 3/4 canes per vine. “I’d like to average two,” Vella says, “but it all depends on the previous year’s growth.”

Chateau Montelena practices sustainable farming. Insect infestations have never been a problem according to Vella, but he has about 750,000 ladybugs released in late spring, “just to make myself feel like I’m doing something.” In addition to eliminating the use of soluble fertilizers and relying on the pomace, wood, manure recipe compost, Vella refrains from using herbicides, relying on an old-fashioned French plow where possible to keep the vineyard free of weeds.

His crew makes one pass with the plow in the spring, preferably before bloom, but always after bud break. Suckering is done during leaf removal, and, during this time, the crew also looks for weeds. The first suckering is done on the trunk and head before bloom.

A mower, hoe plow, and disc are used to handle the cover crop. On the valley floor, the cover crop is mowed after bud break, when weather allows. “We may wait longer than others,” Vella acknowledges, “but we will not allow tractors on the soil when the ground is wet.”

The crew discs between four and eight inches deep, depending on how hard the ground is, and on the hillsides it’s necessary to mow as often as four times per year. “We have to irrigate the hillsides, so we get more weeds there,” Vella notes.

No irrigation is given to most Cabernet Sauvignon vines on the valley floor, but Vella has experimented with irrigation on hillsides to get the right formula. “It’s not on a schedule,” he says. “Just when it looks ready.” He may water up to two weeks before harvest. Typical irrigation for rocky hillside blocks is 6 to 7 gallons/week.

The first thiolux application is after bud break, the second is just before bloom. A typical season would include two applications of thiolux and two or three sulfur dustings.

For frost protection, Chateau Montelena has 13 wind machines and about 25 acres under sprinklers. Hillside blocks are unprotected. Vella plans on a 60-day window for frost after bud break, and in 2004, used wind machines and sprinklers only three times. But in 2005, they came into play 11 times.

An intangible asset
In addition to the viticulture practices employed by Chateau Montelena, another element plays a major role in making the world-class wines for which the winery is known.

A long and special relationship between Vella and winemaker Barrett brings an intangible asset to the winery. Vella and Barrett were classmates at Fresno State and developed a close friendship. Vella graduated with dual degrees in enology and viticulture and afterwards worked as the only full-time employee for a small winery in Napa Valley, handling every aspect of the winegrowing and winemaking process.

In 1985, when Chateau Montelena’s vineyard manager, John Rolleri, was about to retire, Barrett called Vella and offered him the job, saying he was looking for an experienced vineyard manager who also had a winemaker’s perspective. Vella wondered if good friends would be able to work together without ruining the friendship, but he decided to give it a try, and the relationship has worked perfectly and the friendship survives.

The two trust each other implicitly and work very closely together when harvest comes. Vella and Barrett make a joint decision on when to pick, and they have established what they call a “veto power” voting system. If they do not agree, they hold off picking, because both believe it is better to wait than pick too soon.

All these factors — excellent vineyard locations; careful selection of rootstocks and clones to match the soils and climatic conditions of individual blocks; soil management with annual soil analyses; cover crops; and the close working relationship between vineyard manager and winemaker — work together to produce the high-quality grapes that allow Chateau Montelena to sell its Napa Valley Cabernet Sauvignon for $40, estate Cabernet Sauvignon for $125, and Napa Valley Chardonnay for $35/bottle.