The growing season was a period of time during a region or planet's year which was especially conducive to plant growth.
In 2268 when a landing party from the USS Enterprise explored the surface of Argus X, it was the growing season in the hemisphere they had landed on. Spock suggested that the peculiar honey smell James T. Kirk noticed in the air was due to the dissemination of pollen. (TOS: "Obsession")
Draylon II had a long growing season. In 2370, Benjamin Sisko cited this as one of the factors that gave it potential as a home for the Skrreea. (DS9: "Sanctuary")