How is the number of growing degree days (GDD) for corn calculated with a high of 90F and a low of 68F?

Calculating growing degree days (GDD) involves understanding how heat accumulation affects plant growth. GDD is typically computed using the formula:

GDD = (Max Temp + Min Temp) / 2 - Base Temperature.

In the context of corn, the base temperature is generally considered to be 50°F.

For the scenario provided, when the high temperature is 90°F and the low is 68°F, you first average the high and low temperatures:

(90 + 68) / 2 = 79°F.

Next, you subtract the base temperature of 50°F from this average:

79 - 50 = 29 GDD.

So, the correct answer reflects the proper application of the GDD calculation. This shows how the appropriate growing degree day count is determined, which is crucial for predicting crop development stages and optimizing management practices.