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: 7/3/2015        
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 5735 4917 117 Beyond 6th Leaf Beyond 6th Leaf
09/15 5320 4445 120 Beyond 6th Leaf Beyond 6th Leaf
10/01 4818 4026 120 Beyond 6th Leaf Beyond 6th Leaf
10/15 4426 3737 118 Beyond 6th Leaf Beyond 6th Leaf
11/01 4044 3480 116 Beyond 6th Leaf Beyond 6th Leaf
11/15 3884 3321 117 Beyond 6th Leaf Beyond 6th Leaf
12/01 3751 3196 117 Beyond 6th Leaf Beyond 6th Leaf