For beans, the timing of growth stage progressions through the season is dependent on both the variety and environmental cues such as day length, or temperature. The bean growing degree day model developed as part of the CROPTIME project at Oregon State University, uses heat units and time as a method to estimate plant phenological stages through the growing season. This can be helpful as a crop management tool, or to predict harvest timing.

Calculating Growing Degree Days

For this model, a lower temperature threshold of 40F and an upper threshold of 90F is used to calculate growing degree day accumulation beginning at the time of planting. Growing degree days can be calculated from daily high and low temperatures, or via the Pest Prophet app, which uses hourly temperature data for a given field. This can be used to predict flowering and harvest time for the following varieties: 5630, Provider, and Sahara, based on growing degree day accumulation.

Other Common Bean Varieties

For some other Common Bean varieties, there is an older growing degree day model, which can be used to predict anthesis, or timing of flowering. For these models, the biofix should be set when 50% seedling emergence is observed. 50% Anthesis timing can be calculated using the table below, or using the Pest Prophet app.