The ground beneath vineyards and what grows there — in addition to grape vines — could play a role in making wine grape growers in North Carolina and elsewhere along the East Coast more competitive and profitable.

That is the thinking behind a North Carolina State University study of the way wine grape growers produce grapes. N.C. State is one of six universities involved in a five-year study funded by a $3.8 million grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Virginia Tech is the lead institution in the study. Scientists up and down the eastern seaboard will be engaged in a range of projects designed to determine how wine grapes can be grown more competitively in the Eastern U.S.

Excessive rain produces large canopies

N.C. State will receive $841,111 over the five-year life of the grant, said Sara Spayd, professor of horticultural science at N.C. State and North Carolina Cooperative Extension viticulture specialist. Spayd said the N.C. State part of the project will focus largely on determining the optimum way to treat the ground beneath rows of grape vines.

She explained that the relatively large amounts of rainfall in the Eastern U.S. — in North Carolina, around 40 inches annually — can be a problem for wine grape growers. That moisture tends to fuel the growth of the vine canopy — the leaves on a grape vine — and an unusually leafy canopy can be a problem for growers.

If vines grow too vigorously, Spayd explained, fruit quality and yield can be reduced. Growers can spend considerable time and money dealing with excessive canopy growth. Eastern growers are often forced to trim canopies, which adds to the cost of producing grapes. And a big, leafy canopy tends to hold humidity, which can lead to fungal diseases, and gives insects a place to live and hide, both problems that can add to the cost of producing grapes.