Track heat accumulation to time crop growth and pests.
Each day's average temperature above the base contributes heat units, totaled over the growing period. Plants develop on accumulated heat rather than calendar days, so GDD predicts bloom, fruit and pest risk.
Growing Degree Days
Daily GDD = (high + low)/2 - base, floored at 0
Daily GDD = (high + low)/2 - base, floored at 0 Each day's average temperature above the base contributes heat units, totaled over the growing period.
Plants develop on accumulated heat rather than calendar days, so GDD predicts bloom, fruit and pest risk.
This calculator takes 4 inputs: High temp, Low temp, Base temp, Days counted. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.