How I once planted a vineyard in nothing but rock

The amazing story of how I planted a vineyard in nothing but rock and how the property was then sold to a rock star

By RICHARD NAGAOKA & Charles Kamins

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Q: As you may have heard, Madonna recently bought a small ranch up on the Oakville grade, or so the rumor goes. That property had an abandoned gravel quarry on it. According to Napa Valley legend, you once were involved in an experiment on that property, isn't that right?

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Yes, it's a small world after all. It's true. The previous owner engaged me to conduct a feasibility study on a former gravel quarry on the Oakville Grade. Presumably there's only one, so I think we're talking about the same site. I didn't see Madonna, however, during my investigation. Lots of deer though.

The owner wanted to ascertain whether the soils on the property were suitable for grape vines and out of curiosity I proposed to determine if a ten acre pile of rocks could grow grape-vines. Mind you, all the top soil had been removed probably decades ago. The appearance resembled a moon-scape. What better challenge for a bright viticulturalist to reclaim what would ordinarily be considered an unsuitable site for vines.

The Experiment: Prepare vine beds in a rock quarry

Seemingly inhospitable environment of a rock quarry

I know colleagues who have planted in soils so rocky they had to use dynamite to blow a crater into rocky soils and then replace the hole with top soil and grape vines. No doubt the dynamite left behind enough nitrates to sustain a vine for at least the first year.

The proposed experiment was designed as follows: We would test five different rootstocks for their ability to mine a living out of bedrock. At the same time, various planting media to backfill the holes was evaluated. Some of the vines were planted only with rock as growing media and the replicants were planted with imported media such as top soil, compost and polymers. Technically, these media would act like small sponges to which water could be added via drip irrigation and nutrients.

A back hoe was employed to chisel out 50 holes in two different formations of bedrock. Sparks were literally flying during this process. The planting media was backfilled in a bottomless 5 gallon bucket so that all vines received similar quantities of "soil." The control was five gallons of rock with no soil added. This was a test of the viticultural folk-lore that a grapevine will grow on nothing more than rock.

I have been involved with vineyards planted on terraces that are composed almost entirely of fractured pieces of shale or weathering sandstone. A good example would be the terraces at Pine Ridge Winery in the Stag's Leap district off of the Silverado Trail. Observations of those roots after two years revealed an extensive, albeit fine, small diameter root system throughout the aggregate.

I thought to myself, why not?

Back to my experiment. The vines were planted in the late summer of 1997 and evaluated throughout the spring and summer of 1998. The results are that all vines survived with better than expected growth. The vines were irrigated with 0.5 gallons of water per vine per day in the first year and with 0.5 gallons twice a day in the second year.

What was the conclusion? I don't know. I got fired. The client apparently sold the property. However, the vines may still be there. The first crop normally would be due next year.

From the observations I did make, I saw that the vines grew up the stakes in a normal manner. Certainly not as vigorously as along the Napa or Russian River, but far beyond my expectations. Remember, no fertilizers were applied. I couldn't find any difference between the vines that grew only on rock compared to the vines that grew with compost and soil added. Surely, in the long term, nutrient deficiencies should be expected not only in zero soil but with only 5 gallons of top soil or media we should expect that they would need some supplemental fertilizer.

Nevertheless, it seems that vines will, in fact, grow in rock. What kind of grapes or wine may result is still unknown. Perhaps the new owner will continue the experiment. After all, she is a well known rock star. Considering the attributes of hillside vineyards, what better location to evaluate the potential of producing extremely concentrated grape flavors and the resultant wine style than in a rock quarry?

A word about veraison

Pinot Noir grapes in the early stages of veraison

Good news folks, veraison is beginning. This is the stage of fruit development when the grapes begin to turn color. The French tell us that there are 100 days between bloom and harvest. Veraison is the half way stage in the vine's annual cycle. On my California calendar veraison is expected to take place about six weeks from bloom. So set your clocks for six remaing weeks till harvest.

The good news for vineyardists is that if mildew control measures have been successful up to this point, growers can discontinue their crop protection measures because veraison indicates that the grape sugars are between 6-8% degrees brix. Mildew is too dumb to germinate on berries with greater than 8% sugar. Growers can now relax, go on vacation. Many vineyard managers use this time to take a break before the hectic harvest season begins.

Those growers who have not controlled mildew, however, will find that it will continue to grow and cause havoc. If mildew has infected the vines before veraison, it can keep on going through to harvest.

During and after veraison, the berries are much more sensitive to sunburn so if you haven't shoot positioned and leafed by now, you might as well just sleep in till harvest. As long as the berries have been exposed to direct sunlight before and during the green-pea stage, they will not suffer sunburn as readily. However, berries that have not been exposed can get a bad case of sunburn in a hurry at this stage post veraison.

Another good yardstick is to wean the vines off of irrigation because by now they better have enough foliage by now (estimated by some to be at least 14 leaves per cluster) to mature the grapes because the vine should be slowing down vegetative growth so it can get down to the business of producing sugar otherwise there'll be no alcohol.

Veraison is the most visible and important point in the summer phenology of the grape vine. Growers who have made it successfully this far can relax a bit. Sit by the pool, drink some lemonade, relax.

This is a good way to set your clock. Ordinarily we would expect verasion in the first half of July. It appears that it will still be going on through mid-August. So expect harvest to be a bit late this year.

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