Growing Cannabis Seeds in Jacksonville, Florida

Jacksonville’s tropical climate and 298-day growing season make it ideal for cannabis seed cultivation—but only if you time it right. In USDA zone 9a at just 33 feet elevation, your biggest enemy isn’t frost; it’s humidity. With last spring frost on February 10 and first fall frost December 5, you have a long window to work with, but the 80%+ humidity during summer months (May–October) creates serious mold and bud rot risk. Smart Jacksonville growers work within these constraints: start seeds indoors 4–6 weeks before February 10, transplant outdoors after mid-February, and harvest before December. Medical seeds are fully legal here, so you can plan with confidence.

Jacksonville’s near-sea-level elevation means humidity management beats temperature control every time. Your 298-day frost-free window runs from February 10 through December 5—plenty of time for outdoor crops—but hurricane season (June–November) and peak summer heat (90°F+ with intense humidity) demand strategy. Autoflowers and fast-flowering indica genetics finish before late-summer tropical storms hit hardest. Start your calendar backwards from December 5 harvest and you’ll see why October–May outdoor grows avoid the worst of Florida’s wet season and mold pressure.