NOFA Interstate Council: The Natural Farmer. Toward Organic Vineyards. Bob Olsen

The Natural Farmer

Toward Organic Vineyards

Bob Olsen

During the operation of my one-quarter acre research vineyard here on Cape Cod, I have frequently encountered people who, on learning of my interests, have fondly reminisced about an older relative who tended grape vines and made jam or wine. I naturally respond with a ready availability to help the individual carry on the tradition with a couple of their own vines in the back yard.

This then leads into a discussion of the suitability of varieties of grapes for different purposes. Usually, the individual nostalgically remembers the distinctively-pungent Concord flavor and then wonders if s(he) can duplicate the Chalone or Romanee-Conti wine they had the night before.

Native grapes, such as Concord, Catawba, Delaware and Niagara, have been easily grown in the Eastern U. S. for many years because they have been found to be resistant to the diseases that affect the more highly-developed European types and to require little or no fertilizer. The reliable art of raising those labrusca grapes and of converting them to a food is highly gratifying, but everyone should realize that the "foxiness" can never be eliminated by processing. If that unique bouquet is to be valued, then one should go with those varieties.

On the other hand, many wish to advance into emulating table and wine grapes that are becoming available from around the world through modern refrigerated transportation. In this case, the grower must be aware of the more critical conditions that vinifera and hybrid vines require in order to obtain a good yield of clean fruit. Early-on in this history, manures were mulched on the ground around the vines and lead, arsenic and copper/sulfur mixtures were sprayed on every week to kill the bugs. Gradually, synthetic inorganic and organic chemicals have been developed for these purposes that are cheaper, safer and more effective. Within recent years, government regulators, scientists and environmentalists have become aware of some subtle, undesirable effects that are by-products of these developments: elements running-off the land into waters in concentrations toxic to fish, a tendency to kill beneficial micro-organisms in the soil, genetic adaptations of pathogens to become resistant to the toxins and failure of some sprays to completely degrade before market delivery. Such increased sensitivity to an environmental balance of risk to benefit has required the development of what are known as I. P. M. (Integrated Pest Management) and L. I. S. A. (Low Input Sustainable Agriculture) programs in many commercial vineyards: fertilizing, irrigating and spraying only when control tests show that they are needed.

Beyond such cautionary developments, the emergence of a viable market for organic fruit, vegetables and meat has led to efforts to find ways to produce this food with the least application of any toxin. NOFA has been in the fore-front of this grass-roots movement, which is now leading to legislative standards. The growing of organic grapes has been particularly difficult because a sugar content in the fruit of between 15% and 30% invites every living organism to pierce that thin skin for the luscious juice, a condition faced by no other plant.

Commercial vineyards are adjusting to these social pressures for less poison by supporting treatments that either fend-off or confuse the hungry organisms; such agents require much research to find ones that read and counter the "minds of the beasts". This will be a continuing, expensive battle. My own research has focused on methods used by "Mother Nature".

The fact that all grape vines have tendrils suggests that they prefer to grab on to a tree for support so that they can get maximum exposure to sunlight. Since the bird "drops" the seed near the trunk, on average, it follows that the growing vine, through the millennia, has become dependent for its continued, competitive existence on the breakdown products of wood and, possibly especially, bark. On Cape Cod, wild labrusca vines are found only in low-lying areas that have sustained trees for hundreds of years; other areas were denuded (until recently) for fire wood in the early 1770's. On surface, then, all we need to do is feed the vine with old wood.

One difficulty in trying to adapt these conditions to vinifera and hybrids is that all forest litter contains considerable amounts of Agrobacterium tumefaciens, a bacterium that has an uncommon ability to insert its genes into the cambium cells under the wounded bark of sensitive trunks. Because the bark of vines has a vertical orientation, while that in trees is circumferential, vinous infection by A. t. results in a compartmentalizing tumor (crown gall) that extends completely around the trunk, thus killing it; tree infection merely ends with a vertical slit that lips over in several years. This, then, says that we should keep the old wood away from the vine trunk at the soil line by an impervious, stable barrier.

By putting these ideas together, we are well on our way to attempting to grow the vine and produce grapes without the use of synthetic fertilizers and pesticides. The best planting method devised to date is as follows: "Dig a 16" diameter hole in the selected area (6 hours sunshine each summer day) about 16" deep. Suspend the 1-2 year-old vine in the center of the hole so that the roots are evenly distributed and the rootball is about 10" deep. Shovel back in slowly an intimate mixture of the topsoil with about 15% of well-aged vegetable compost up to the rootball; add water and slosh to a slurry. Let drain and continue back-filling until the soil level permanently reaches the rootball. Then add one gallon of wood compost (obtained from the base of a large pine tree, from bin-manufactured product or from an old rotted stump), stomp down by foot and back-fill with coarse, washed sand up to soil level, trimming off any adventitious roots on the upper trunk. Water to settle and encircle the vine at 6-8" radius with an overlapped truck-tire flap 8-10" high. Add sand inside and old wood/bark outside to within 1" of the top of the flap. Water once a day for a week and once a week for a month. An existing vine can be rehabilitated by digging out soil to the rootball and continuing on as above. The surface roots of each vine should be fed by a mulched area of 4' by 4'. No further nutrients need be added to the soil other than replenishment of the wood mulch as it slowly ages and consolidates. In order to maintain "organic" status, the vines should be treated by only those pesticides authorized by the NOFA (or State) Certification Board. The choice of own-rooted or grafted vines to start will depend on the soil type, but both respond well to the above system. The vigor of the mature vine will decide whether the cordon training on a trellis should be bi-, quadri- or hexa-lateral; pruning should be simple side- and top-skirting."

My own vines here on Cape Cod, representative of 50 vinifera, hybrid and labrusca varieties, have been so organically cultured for up to 10 years. What are the results? On average, by actual trunk area measurement, wood-treated vines respond with eight times greater growth over untreated vines. This would not be true in New Zealand, where the soil is naturally nutritious from the much more recent tree remains; there, viticulturists have a difficult time to adequately control the robust vine growth without any fertilizer. In regard to infection and insect attack, my vines have been relatively pest-free for nine out of ten years, and in that very humid exception, the mold on the grapes did not affect the quality of the wine made from them. I have seen no effects on the vines of the tendency of the wood treatment to slightly acidify the soil (pH = 5.3 normal and 5.1 treated). One major benefit of the flap has been that crown gall has been completely eliminated. I have not studied the relative fruit yields of vines.

What has been the experience of other organic grape growers? The only reports that I have seen have been about the mere existence of one in Harquahala, NM, three in Southern California and one in Himrod, NY. Tracy Frisch, in Albany, NY, is collecting information on organic fruit preparatory to publishing a review. Relatedly, Professor Harry Hoitink at Ohio Sate University has obtained a patent covering the use of pine tar bark compost in starter mix to suppress damping off of poinsettia and cyclamen.

So far, I have found satisfactory responses with the following varieties that are suitable for this cool Region I climate: Aurore, Castel 19637, Cascade, Chardonnay, Einset, Foch, GR-7 and 8, GW-8, Pinot Noir, Valiant, Vanessa, Veeport and Vincent. In Region II, a more-temperate and medium-length growing season, the varieties that would do well with the organic wood treatment are Baco Noir, Chancellor, Gamay Beaujolais, GW-9, J-S 23416, Landal, Pinot Blanc, Riesling, Seyval Blanc, Traminer and Vidal. For hot, long-season areas, Barbera, Cabernet Sauvignon, Chambourcin, Chelois, Malbec, Merlot, Sauvignon Blanc, Semillon, Vignoles, Villard Blanc and Villard Noir are recommended.

In this 20th anniversary year of Earth Day, it would be fitting for an academic research center staffed with specialists in microbiology, horticulture, plant pathology, epidemiology and viticulture to statistically determine the merits of this anecdotal experience through controlled experiments. Efforts to date to persuade one to start such a study have not been successful. If it is reliable, many improvements are possible.

I hope that this short summary on natural grape-growing will provide orientation for others in a neglected area of organic agriculture. Those who do try my suggestions are invited to let me know about their problems, successes and improvements.

Bob Olsen, 300 Country Lane, Eastham, MA 02642-3329, (508) 255-6205

This page was last modified on February 25, 2004 at 9:30:18 PM.

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