Grape Growing 101 - Viticulture Iowa State University

Grape Growing 101
Keys to Success
Eli Bergmeier
Viticulture Technician
Golden Hills RC&D
eli.bergmeier@goldenhillsrcd.org
(712) 482-3029
Presented at the
Iowa Grape Growers Association
Annual Conference
Des Moines, Iowa
January 31, 2004

Essential Success Factors
• Market
• Site Selection
• Cultivar
Selection
• Inputs
– $$$
– Materials
– Management
Photo courtesy Mike White, ISU Extension

Market Potential

Market Potential
• Three primary markets for grapes:
– Wine
• 95+% of the present IA commercial market
• Limited market size
–Juice
– Fresh consumption, jelly, and other food
products
• Over-production will result in reduced
fruit prices or unsold fruit.

Gallons
IA Wine Market
Projected IA Wine Production Vs. 5% and 7.5%
Market Share Values
250000
200000
150000
100000
50000
Reported Wine Production 5% Market Share
7.5% Market Share
0
2002 2003 2004 2005 2006 2007
Year
Justification: reported production figures taken from 28 completed winery surveys submitted to
’03 I.D.A.L.S. Wine Industry Survey. Projected market share values derived by extrapolating
’92-’02 wine excise tax increase rates through ’07 and adding reported IA wine production.

IA Winery Base Preferences
Portion of Annual Production
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Iowa Wine Bases, 2002 - 2007
2002 2003 2004 2005 2006 2007
Year
Estate Grape
Grower Grape
IA Grape
Imported Grape
Grape
Fruit/Mead
Justification: figures derived from 28 completed winery surveys submitted to ’03 I.D.A.L.S.
Wine Industry Survey.

IA Grape Demand by Wineries
Acres
300
250
200
150
100
50
0
Est. Acres of Bearing IA Grapes Needed to Meet Reported
Demand at Various Production Levels
Reported Demand 5% Market Share 7.5% Market Share
2003 2004 2005 2006 2007
Year
Justification: estimated number of bearing grape acres necessary to supply stated IA
wine production levels given wine base preferences reported on 28 completed winery
surveys submitted to ’03 I.D.A.L.S. Wine Industry Survey. Assumes finished wine
yield of 525 gallons per acre.

Acres
Reported IA Grape Acres
300.00
250.00
200.00
150.00
100.00
50.00
0.00
Reported Commercial IA Vineyard Acres: Bearing + Unbearing
2002 2003 2004 2005 2006 2007
Year
Justification: figures compiled from 163 completed vineyard surveys submitted
to ’03 I.D.A.L.S. Wine Industry Survey. Assumes no attrition.

Keys to Success
1. Know your market
2. Seek a secure
buyer
– Develop relationships
– Contract?
3. Plant in-demand
cultivars
“Marketing is finding out
what your customer wants
and giving it to them.”
Tim Cohn; consultant

Site Selection

Site Selection Considerations
• Climate
– Macro-climate
– Meso-climate; topography
• Soil characteristics
• Distance from sources of herbicide
drift
• Other concerns:
– Access to irrigation source
– Geometric regularity and plot shape

• Macro-climate
concerns:
influenced by
weather patterns
– Winter low
temperatures
– Average season
length (frost free days)
– Growing degree days
– Annual precipitation
Climate
• Meso-climate
concerns: heavily
influenced by
topographic
position

U.S.D.A. Cold Hardiness Zones
Zone 4B
-20 to -25º F
Zone 5A
-15 to -20º F
• Locate the vineyard site in a region that is conducive to
the survival of in-demand cultivars.

IA Frost-free Days
• Minimum frost-free days for commercial cultivars
ripening early - 150 days; early mid-season - 160
days; late mid-season - 170 days. Image courtesy
Dr. Paul Domoto, I.S.U.

IA Growing Degree Days
• Sites offering less than 2500 G.D.D. should be
considered unfavorable for grape production. Image
courtesy of Dr. Paul Domoto, I.S.U.

IA Annual Precipitation
• Iowa’s climate typically supplies sufficient precipitation to foster successful
grape production. However, seasonal droughts do occur, and soil
characteristics can negatively impact moisture availability. Image courtesy
of Dr. Paul Domoto, I.S.U.

Topographic Position &
Meso-climate
• Favorable sites offer:
– Elevation: to avoid collection of cold air contributing to late
spring, and early fall frosts.
• Situate vineyard ≥ 50 feet above nearby low-lying areas.
– Slope: to facilitate cold air and surface moisture drainage.
• Greater than 1.5% is desirable, but less than 15% is
necessary for safe equipment operation.
– Exposure to sunlight and wind.
• Full exposure to sunlight and air movement is important.
– Aspect
• South commonly preferred, but each orientation offers
assets and liabilities.

Find the Good Sites…

• Favorable sites offer:
Soil
– Adequate depth of uncompacted soil.
• Greater than 2’; 3’ preferred
• Consult County Soil Survey; dig soil pits if in doubt
– Adequate internal drainage.
• Grapes generally grow poorly in oxygen-deficient
soil!
• Defined by County Soil Survey as “well drained” or
“moderately well drained.”
• Perform percolation test if in doubt.
– Seasonal high water table lower than 4’; 6’
preferred
• Consult County Soil Survey

Soil, Cont’d
• Favorable sites offer:
– Proper soil pH and adequate nutrient
concentrations.
• Dual depth pre-plant soil analysis for pH, organic
matter, P, K, and Zn concentrations is essential.
• Soil pH between 5.5 and 7.0 is workable for most
cultivars adapted to IA climatic conditions; soil pH
between 6.0 and 6.5 is preferred.
– Moderate to high available water capacity.
– Moderate organic matter levels.
• 1.0 to 4.0% is workable; 2.0 to 3.0% is preferred
– Low harmful nematode populations.
– Lack of herbicide residue; e.g. atrazine.