Growing degree-day

Growing degree days (GDD), also called growing degree units (GDUs), are a heuristic tool in phenology. GDD are a measure of heat accumulation used by horticulturists, gardeners, and farmers to predict plant and animal development rates such as the date that a flower will bloom, an insect will emerge from dormancy, or a crop will reach maturity. GDD is credited to be first defined by Reaumur in 1735.^[1]

^ Ferchault de Réaumur, René Antoine (2023-02-06). "Observations du thermometre, faites a Paris pendant l'annees 1735, comparees a celles qui ont ete faites sous la ligne, a l'Isle de France, a Alger et en quelques-unes de nos isles de l'Amerique" (PDF). Mémoire de l'Académie royale des sciences. Alt URL.

[1] Ferchault de Réaumur, René Antoine (2023-02-06). "Observations du thermometre, faites a Paris pendant l'annees 1735, comparees a celles qui ont ete faites sous la ligne, a l'Isle de France, a Alger et en quelques-unes de nos isles de l'Amerique" (PDF). Mémoire de l'Académie royale des sciences. Alt URL.

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