Imed Dami’s Ohio Winegrape Trials Update
On February 21st, Dr. Imed Dami, Associate Professor of Horticulture and Crop Science at OSU, updated participants of the Ohio Wine and Grape Conference on research findings of OSU’s “Winegrape Variety Evaluation Trials.” Dami heads the 8-10 year study which evaluates the viticultural characteristics and wine quality potential of more than 30 grape cultivars and clones new to Ohio.
The goal of the research is to identify which grapes are best suited to various areas of the state. Toward that end, planting has been done at three locations — one in the center of the state, one in the north and one in the south. Most plantings in each of the three areas are vinifera varieties.
Some of the findings presented at the conference are given below:
Current grape plantings
There is an increasing interest from growers in the red varieties. ‘I assume this is because of consumer interest in red wines,” says Dami. ‘Ohio already had a good reputation with white wines, but winery owners are now interesting in producing good reds.” At the same time, there has been a decline in the number of acres planted in Concord grapes.
One of the key factors in the trial is the number of growing days in each region. There are 2,500 growing days in northern Ohio, 2,700 in central Ohio and 3,200 in southern Ohio. The numbers of frost-free days in each area are: 175, 162 and 180 respectively. That means a difference ranging between 112 and 167 days for the grapes to ripen.
Cold and freezing
A second factor, and maybe the most important, is cold. ‘Cold affects production more than insects or disease,” says Dami, who adds: ‘Winter injury is the most limiting factor for sustainable production in Ohio.” Freezing tests, conducted as part of the study, show Barbera and Malbec may fare the best. When bud injuries are considered, Pinotage, Gamay Noir and Chardonnay did the best at the Central location, where low temperatures average minus three degrees. In the northern location, Regent, Pinot Noir and Albarino had the least damage. Dolcetto and Durif (Petite Syrah) were among the very tender varieties that show the most damage in cold.
Crown gall is far more damaging than insects as it can kill the entire vine. Research shows the Malvasia grape is among the most susceptible. If affected by crown gall, 62% of the vine is killed, as opposed to Gamay Noir, where only 5% of the vine will be affected if infected by crown gall.
If spring de-hilling is delayed, scion roots may form on some grape varieties. However, OSU studies show that Merlot, Syrah, Lagrein, Cabernet Sauvignon and Gamay Noir showed no scion rooting after delayed de-hilling. ‘But don’t delay de-hilling for too long,” cautions Dami.
The two most promising viniferas for Ohio at present are Gamay Noir and Regent. ‘They both have a low winter injury rate and mid-season maturity,” says Dami. “However, more research needs to be done.” Growers who plan to plant new vinifera varieties this spring are asked to call the OSU Extension office (330) 263-3825 for information on which varieties to consider.
Excuse my ignorance I am a little confused on the number of growing days. The article says: 2,500 growing days in northern Ohio, 2,700 in central Ohio and 3,200 in southern Ohio.
There are 364 days in a year, what does 2500, 2700, 3200 growing days mean?
Here’s a link to Iowa State University for a technical explanation of growing degree days