by Sanne Kure-Jensen
“Start by deciding what types of wine you want to produce and then find a suitable site,” said Mark Chien, program coordinator for the Oregon Wine Research Institute. Vineyard production is a balance of site, soils, variety selection, pruning and weather conditions. Chien shared his site selection and vineyard design recommendations at the New England Vegetable & Fruit Growers Conference.
This term describes the influence and interaction of soil, climate, plant, viticultural practices and winemaking techniques to create a distinct and sometimes regional flavor to wine. In a new wine region, Chien said, soils and climate offer about 20 percent influence each on wine terroir. Plant characteristics affect about 10 percent of wine’s terroir. The remaining, and strongest, influences on the wine are viticulture and wine making practices.
Seek a site with the most virtues and the least flaws. In cool and cold regions, be sure to seek warm fields. Sloped fields should face southeast to southwest and have a maximum slope of 30 percent. Convex fields promote air movement and help drain excess water.
Soils should be light and well drained with low to medium plant available water and nitrogen. Avoid wet soils. Review USDA soil maps and be aware of and seek out rain shadows. Open fields are best — avoid large obstructions and trees.
Perform soil tests for each potential field or variety block. Soil fertility should be moderate with organic matter of 1 – 3 percent. Gather data on soil pH, depth to bedrock and average rock size. Talk to experts and local growers, and utilize USDA and Extension resources as well as regional fruit tree and grapevine growers to learn potential for success and hazards.
Determine site capacity, fertility, available water and the vine size the site will support. Select rootstocks and grape varieties whose vigor and ripening requirements match the site capacity.
Select a trellis system: single vertical or divided, high or low. Determine fruit wire and canopy heights, and plan appropriate vine spacing for the grapevine variety based on expected vine size. Larger vines such as native and many hybrids need more space between rows and vines. Vines grown on lighter soils with lower expected yield/vine can be spaced closer together.
Rows should be far enough apart to fit tractors, hedgers and harvesting equipment. Remeber to account for the extra space for vines trained to high wire systems. Orient rows northeast to southwest for ideal sunlight exposure and consider the potential impacts of prevailing winds and slope contours.
Select the appropriate trellis system and training schedule to fit the grape vine variety’s vigor and management needs. “Pruning is the Holy Grail of viticulture. Vineyard managers seek ideal pruning techniques for proper vine balance,” said Chien.
Consider the vineyard floor. Plan for grass, legume blends or other cover crops between the rows, and decide the width of the weed-free area under the vines, which will effect soil erosion. If you will use drip irrigation, create a plan to drain the systems each fall.
Also consider other variables, such as: Are there public or private roads, rock outcrops, wetlands, outbuildings, utility easements or water restrictions near this location that may affect a vineyard operation? Do local ordinances allow vineyards and wineries? Are neighbors supportive of a vineyard operation?
Learn from the Best
Chien urged new vineyard owners and managers to hire expert vineyard consultants. The money spent on consultants will save time, reduce mistakes, improve production quality and help you have fun.
Chien quoted John Thull, University of Minnesota research vineyard manager, “for the best wine, grow everything like vinifera.” He suggested managing the canopy for vine vigor and the fruit zone for cluster numbers and position. Disease and pest management is critical to producing clean and optimal fruit. Harvest at proper ripeness for best wine quality. Manage for deacclimatization in fall to minimize winter injury. In colder climates, it may be appropriate to hill soils to protect graft unions from winter injury.
Vineyard site selection and design
by Sanne Kure-Jensen