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: 1/25/2015        
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 2349 1989 118 Beyond 6th Leaf Beyond 6th Leaf
09/15 1934 1518 127 Beyond 6th Leaf Beyond 6th Leaf
10/01 1432 1099 130 Beyond 6th Leaf 4th Leaf
10/15 1039 809 128 3rd Leaf 2nd Leaf
11/01 658 553 119 1st Leaf 1st Leaf
11/15 498 394 126 Emergence Complete Emergence Complete
12/01 364 269 136 Emergence Complete Germination Complete