FruitWatermelon
All Sweet Watermelon
All Sweet Watermelon is a heat-loving heirloom descended from the legendary Crimson Sweet, bred to deliver exactly what its name promises: intense sweetness with minimal seeds. This open-pollinated picnic watermelon produces large fruits with brilliant red flesh and grows reliably across hardiness zones 3 through 13, reaching harvest in 100 to 109 days. It's a workhorse for gardeners who want genuine flavor without the hassle of spitting out seeds, and its heat tolerance means it thrives even in challenging summers.
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
Hover over chart points for details
Highlights
The bright red, mouth-watering flesh and sparse seed count make this variety a revelation for anyone tired of traditional seeded watermelons. An authentic heirloom with real lineage, All Sweet combines the proven genetics of Crimson Sweet with the practical benefits of a seeded type that actually tastes exceptional. The heat tolerance and reliable 100 to 109-day maturity window mean you can count on it to deliver even when summer feels brutal.
Common Uses
All Sweet is a classic picnic and garden watermelon, perfect for slicing into thick wedges and eating fresh on hot days. The sparse seed count makes it far more enjoyable raw than heavily seeded varieties. Its large size and sweet flesh suit it to summer gatherings, family meals, and the simple pleasure of pulling a ripe melon from the garden and cutting into it immediately.
Growing Timeline
No timeline data available yet for this variety.
Care Instructions
Direct Sow
Direct sow All Sweet watermelon seeds into warm soil after all frost danger has passed and soil temperature reaches at least 70 degrees Fahrenheit, ideally warmer. Sow seeds 1 inch deep, spacing them 36 inches apart in rows 120 inches apart. Thin seedlings to the strongest plant at each spacing once they develop true leaves.
Harvesting
Harvest All Sweet watermelons when they reach full size, typically after 100 to 109 days from planting. Look for a creamy yellow spot on the bottom of the melon where it rested on soil, which signals ripeness. The skin should feel firm and waxy rather than sticky, and the melon should sound hollow when you thump it with your palm. Cut the stem cleanly rather than pulling the fruit from the vine to avoid damaging the plant.
Growing Calendar
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Companion Planting
Pests & Diseases
Ecology & Traits
Edible
Scientific Classification
Citrullus lanatus
Family
Cucurbitaceae
Genus
Citrullus
Growth Habit
Vining
Native Status
L48 (I)PR (I)
History & Origin
“All Sweet Watermelon carries genuine heritage in its veins. Developed as a sister line of the iconic Crimson Sweet watermelon, it has held its place in seed collections for decades, earning status as a true heirloom. Unlike many modern hybrids, All Sweet remained open-pollinated and non-GMO, allowing farmers and home gardeners to save seed and maintain the variety themselves. Its long track record in gardens proves that sometimes the best varieties are the ones that endure because they simply work.”