FruitWatermelon
Florida Giant Watermelon
Florida Giant Watermelon is a heirloom giant that delivers massive, perfectly round fruits weighing 30 to 50 pounds in just 90 to 99 days. Developed in 1940s Florida by Melville Dillon, this open-pollinated variety thrives across hardiness zones 3 through 13 and produces seeded melons with outstanding heat tolerance. Its vigorous vining growth and proven productivity make it a centerpiece variety for gardeners willing to give it space and full sun.
Photo © True Leaf Market
Growing Conditions
USDA Zone
3-13
Sunlight
Full Sun
Water
High
Soil
Well-drained, Sandy Loam, Fertile
Growth Stats
18 in
Height
TypeVining
Spacing
36
Plant Profile
Sunlight
Full Sun
Water
High
Zones
3-13
Size
18in H x ?in W
Growth
—
Care
Moderate
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Highlights
This round giant was born from 1940s Florida breeding and carries the nickname Cannon Ball for its perfectly spherical shape. It produces watermelons substantially larger than many modern varieties, regularly reaching 30 to 50 pounds on a single vine. The open-pollinated genetics mean you can save seeds year after year, adding a layer of self-sufficiency that appeals to serious gardeners and heritage seed keepers.
Common Uses
Florida Giant Watermelon is grown for fresh eating, with the large fruits sliced and served chilled during warm months. The high water content and seeded nature of the melon make it suitable for traditional seed-spitting enjoyment and seed saving, roles central to its appeal among heritage gardeners.
Growing Timeline
No timeline data available yet for this variety.
Care Instructions
Start Indoors
Start seeds indoors 3 to 4 weeks before your last spring frost in soil temperatures of 70 to 85 degrees Fahrenheit. Keep seedlings under lights or in a bright window to prevent legginess.
Transplant Outdoors
Transplant seedlings outdoors after all frost danger has passed and soil has warmed to at least 60 degrees Fahrenheit. Harden off seedlings over 7 to 10 days before moving them to their permanent location. Space plants 36 inches apart in rows 120 inches apart to give vines ample room to sprawl.
Direct Sow
Direct sow seeds outdoors once soil temperature reaches 70 degrees Fahrenheit and all frost danger has passed. Sow seeds 1 inch deep and thin to 36-inch spacing once seedlings have established true leaves.
Harvesting
Florida Giant watermelons mature in 90 to 99 days from transplanting. Harvest when the bottom spot (where the melon rests on the ground) turns from white to pale yellow or cream color, and when a hollow thump sounds when you tap the melon with your knuckles. The melon should detach cleanly from the vine when gently twisted; if it resists, wait another day or two.
Growing Calendar
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Companion Planting
Ecology & Traits
Edible
Scientific Classification
Citrullus lanatus
Family
Cucurbitaceae
Genus
Citrullus
Growth Habit
Vining
Native Status
L48 (I)PR (I)
History & Origin
“The Florida Giant emerged in the 1940s from the breeding work of Melville Dillon in Florida, where watermelon cultivation had deep roots in the state's agricultural identity. Dillon's work produced a variety so distinctive it earned an alternate name, Cannon Ball, referring to its unusually round shape compared to the oblong melons more common in commerce. As an open-pollinated heirloom, it became a living archive of mid-century American watermelon breeding, preserved and passed down by gardeners who valued both its productivity and its genetic stability.”