Blacktail Mountain Watermelon
Citrullus lanatus 'Blacktail Mountain'
Developed in Idaho for short-season growing, this remarkable heirloom produces full-sized, incredibly sweet watermelons in just 75 days even in cool climates. The round, dark green fruits with subtle stripes contain bright red flesh that rivals any long-season variety for flavor and sweetness. Perfect for northern gardeners who thought they couldn't grow watermelons.
Harvest
70-75d
Days to harvest
Sun
Full sun
Zones
3–8
USDA hardiness
Height
4-8 inches
Planting Timeline
Showing dates for Blacktail Mountain Watermelon in USDA Zone 7
All Zone 7 melon →Zone Map
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Blacktail Mountain Watermelon · Zones 3–8
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | May – May | June – July | June – August | September – October |
| Zone 4 | April – May | June – June | June – July | September – October |
| Zone 5 | April – April | May – June | May – July | August – October |
| Zone 6 | April – April | May – June | May – July | August – September |
| Zone 7 | March – April | May – May | May – June | July – September |
| Zone 8 | March – March | April – May | April – June | July – August |
| Zone 9 | February – February | March – April | March – May | June – July |
| Zone 10 | January – February | March – March | March – April | May – July |
Complete Growing Guide
Light: #yellow flowers#showy fruits#vegetable garden#edible fruits#edible garden#fruits summer#vine#warm season vegetable#edible#annual#early childhood#child#children#preschool#early care#easy edibles#hortcontest. Soil: Loam (Silt). Soil pH: Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Water: SIT-troo-lus la-NAY-tus. Height: 0 ft. 4 in. - 0 ft. 8 in.. Spread: 5 ft. 0 in. - 10 ft. 0 in.. Growth rate: Medium. Maintenance: Medium. Propagation: Seed. Regions: Coastal, Mountains, Piedmont.
Harvesting
The plant produces melons which are large modified berries called a pepo. They are rounded to oval mottled green with darker green rind. Black, cream or mottled colored elliptic seeds. Flesh general red or pink but can also be yellowish.
Color: Green. Type: Berry. Length: > 3 inches. Width: > 3 inches.
Garden value: Edible
Harvest time: Summer
Bloom time: Spring, Summer
Edibility: The fruit can be eaten raw or pickled. The rind is edible after cooking.
Storage & Preservation
Whole Blacktail Mountain watermelons store best at room temperature (70-75°F) for up to one week, developing optimal flavor and texture. Refrigeration before cutting actually diminishes the sweet flavor this variety is prized for. Once cut, wrap pieces tightly in plastic wrap and refrigerate for up to 5 days.
For preservation, the sweet flesh freezes exceptionally well when cubed and frozen on baking sheets before transferring to freezer bags—perfect for smoothies and agua frescas. The high sugar content makes excellent watermelon juice that can be frozen in ice cube trays for concentrated flavor additions. Dehydrated watermelon leather preserves the variety's distinctive sweetness, while pickled watermelon rind creates a traditional preserve that takes advantage of the fruit's tender, thin rind. Avoid canning the flesh as it becomes mushy and loses the variety's prized texture.
History & Origin
Blacktail Mountain watermelon was developed in the 1990s by Glenn Drowns of Sand Hill Preservation Center in Iowa, specifically bred for northern gardeners struggling with short seasons and cool nights. Drowns selected parent varieties based on cold tolerance and early maturity, crossing short-season melons from Montana gardens with hardy varieties that could set fruit reliably in temperatures that stopped other watermelons.
The variety gets its name from the Blacktail Mountains of southwestern Montana, where some of the original breeding material originated from homestead gardens. These mountain gardens, with their extreme temperature swings and short frost-free periods, provided the perfect proving ground for developing this remarkable cold tolerance.
As an open-pollinated heirloom, Blacktail Mountain represents a successful modern breeding effort focused on climate adaptation rather than commercial shipping qualities. It quickly gained popularity among northern gardeners and seed savers who had previously been unable to grow quality watermelons, making homegrown watermelons possible in previously impossible climates.
Advantages
- +Attracts: Bees
- +Edible: The fruit can be eaten raw or pickled. The rind is edible after cooking.
Companion Plants
Plant Together
Nasturtiums
Trap crop for cucumber beetles and squash bugs, repels aphids
Marigolds
Repel nematodes and cucumber beetles with their strong scent
Radishes
Deter cucumber beetles and squash vine borers, mature quickly without competing
Beans
Fix nitrogen in soil to benefit heavy-feeding watermelons
Catnip
Repels ants, aphids, and cucumber beetles more effectively than DEET
Oregano
Repels cucumber beetles and provides ground cover to retain soil moisture
Corn
Provides vertical structure and shade, traditional Three Sisters companion
Sunflowers
Attract beneficial insects and provide windbreak protection
Keep Apart
Fennel
Allelopathic compounds inhibit germination and growth of melons
Tomatoes
Compete for similar nutrients and space, both susceptible to similar fungal diseases
Potatoes
May stunt melon growth and both crops attract similar harmful insects
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #167765)
Pests & Disease Resistance
Resistance
Good cold tolerance, moderate disease resistance
Common Pests
Cucumber beetles, aphids, squash vine borers
Diseases
Anthracnose, fusarium wilt, bacterial fruit blotch