Growing Degree Day Model for the Early Growth and Development of Cereals
This heat driven early growth and development model for cereal crops is found in Early Growth and Development of Cereals (Karow, et al., 1993 ). Created jointly by Oregon State University and USDA Agricultural Research Service (ARS) scientists, it is based on cumulative growing degree days from the time of seeding.  An initial seeding depth of 2 inches was used for model prediction and the output will update automatically based on the current number of growing degree days.  This is a simple model and actual development can be affected by differences in variety, climate extremes, disease stressors and other factors.  However, under normal circumstances this model is considered fairly accurate.  The model is predictive through development of the sixth leaf, and should not be considered a substitute for checking field conditions.
PDF - Karow, et al., 1993        
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Autoupdate: 2/12/2016        
Growing Degree Days are in farenheit using base 32 which is suitable for winter wheat.
Seeding Current Crop Year 30 Year (81-10') % of normal Plant Stage Plant Stage
Date GDD  Average GDD GDD Current Predicted 30 year Normal
09/01 2128 2093 102 Beyond 6th Leaf Beyond 6th Leaf
09/15 1701 1622 105 Beyond 6th Leaf Beyond 6th Leaf
10/01 1287 1203 107 5th Leaf 4th Leaf
10/15 933 913 102 3rd Leaf 3rd Leaf
11/01 601 657 91 1st Leaf 1st Leaf
11/15 399 498 80 Emergence Complete Emergence Complete
12/01 354 373 95 Emergence Complete Emergence Complete