The Crush - December 2019 - 1

Volume 46 Issue 12 December 2019


Grafting an Established Vineyard to a New Variety
By Ted Rieger
In a challenging winegrape market, grafting an established
vineyard to a higher demand grape variety, or one better suited
to site conditions, may be an option for some growers to improve
grape sales and quality and prolong a vineyard's lifespan.
Field grafting, also called "top-working," offers advantages over
vineyard removal and replant. Economic advantages include
lower costs by retaining existing infrastructure, trellis and
irrigation systems, and established rootstocks. Converting to a
different variety can often be done in one season with one year
of lost production, compared with about three years to produce
a crop after replant. As with planting a new vineyard, growers
should work with a grape buyer to select a desired variety, and if
possible, obtain a contract.
Grafting may be a favorable choice under these conditions:
* The vineyard does not have virus or disease issues, or serious
soil pests - including nematodes and overwintering mealybugs
- that will impact health and productivity. If vines have eutypa
or canker fungal diseases and the infection has not extended
into the trunk, grafting may still be viable and may help reduce
fungal issues.
* Vines are healthy and relatively vigorous, and rootstocks have
many productive years remaining.
* The trellis system and vineyard infrastructure are in good
* The existing rootstock and vineyard site (soils and
climate) are suitable for the new variety.
* The new variety can provide enough
years of production and income to justify
conversion costs.

Photo courtesy of
Top-Notch Grafting

Although in-field top-working is commonly performed in spring
(March to June) in California, Dave Komar of Top-Notch Grafting
and Vineyard Services recommends growers start planning in
early winter by contacting a grafting service to schedule work,
line up vine material, and do initial vineyard prep work.
Established in 2010 in Sonoma County, Top-Notch crews have
worked in the North Coast, Lodi, Sierra Foothills and Oregon.
Komar expects more interest this year in top-working to change
varieties, including to niche market varieties. He is working with
a Mendocino County grower who was unable to sell a muscat
crop in 2019 and plans to graft over to vermentino.
Raul Rodriguez III, the third generation of a family performing
grafting services for more than 50 years, is chairman of The Graft
Corporation International based in Delano. The company has


The Crush - December 2019

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