Variety field guide
What to expect from Black Diamond Watermelon Seeds
Black Diamond Watermelon seeds produce red watermelon, commonly 35-50 lb under generous spacing and a long warm season, on vining/climbing plants.
Read the complete product descriptionTraits, flavor, garden use, variety notes, and the full catalog record
Black Diamond Watermelon seeds produce red watermelon, commonly 35-50 lb under generous spacing and a long warm season, on vining/climbing plants. It is best suited to large gardens, family gatherings, market displays, and growers who want an imposing heirloom watermelon. sweet, juicy, old-fashioned red watermelon flavor Grow enormous dark-rinded watermelons with sweet red flesh and classic Southern garden presence.
About Black Diamond
Black Diamond is an annual watermelon with red color, 97–120 in mature height or spread, and a vining/climbing habit. Harvest form or size: commonly 35-50 lb under generous spacing and a long warm season. Botanically it is Citrullus lanatus (Thunb.) Matsum. & Nakai. Maturity or first bloom: 80-89 Days; germination: 5-10 Days at 75–90 °F. Best for large gardens, family gatherings, market displays, and growers who want an imposing heirloom watermelon. Sweet, juicy, old-fashioned red watermelon flavor.
History and provenance
Black Diamond is a long-circulated American watermelon associated with Southern gardens and large-fruited summer harvests. Exact introduction stories vary, so the variety is best presented through its documented garden traits rather than a single unsupported origin claim. Botanical record: Citrullus lanatus var. lanatus. The broader crop history is kept separate from the documented history of the named variety. Where an exact breeder, introduction date, family story, or cultural attribution cannot be supported by a credible record, repeated claims are not presented as certain. Black Diamond watermelon seeds produce very large, dark-rinded watermelons with deep red flesh. The defining kitchen quality is sweet, juicy, old-fashioned red watermelon flavor. Black Diamond watermelon seeds are warm-season seed. The vines need full sun, warm soil, fertile drainage, and steady moisture while fruit is sizing.
Growing facts
| Scientific name | Citrullus lanatus (Thunb.) Matsum. & Nakai |
|---|---|
| Life cycle | Annual |
| Maturity / first bloom | 80-89 Days |
| Germination | 5-10 Days at 75–90 °F |
| Seed depth | 1 in |
| Plant height / spread | 97–120 in |
| Growth habit | Vining/Climbing |
| Spacing | 36 in between plants; 48 in between rows |
| Sunlight | Full sun |
| Soil | Loamy; pH 6.0–6.5 |
| Water | Moderate |
| Support | No-Support |
Starting Black Diamond from seed
How to grow Black Diamond Watermelon
Botanical identity: Citrullus lanatus (Thunb.) Matsum. & Nakai. Life cycle: Annual.
Sow 1 in and use a seed-zone temperature near 75–90 °F. Expected emergence: 5-10 Days. No stratification; direct sow into warm soil or start briefly in biodegradable cells and transplant young
Plant during Late Spring. Space plants 36 in apart with 48 in between rows or planting bands.
Provide Full sun, moderate water, and loamy near pH 6.0–6.5. Support: No-Support.
Garden performance and care
Give Black Diamond enough room for its vining/climbing growth. Direct irrigation to the soil, keep developing fruit on dry mulch or boards where rot is common, and leave seed-saving fruit on the plant beyond the eating stage. Expected emergence is 5-10 Days; the listed maturity or bloom timing is 80-89 Days.
Harvest, bloom, and uses
Black Diamond is best for large gardens, family gatherings, market displays, and growers who want an imposing heirloom watermelon. Harvest form or size: commonly 35-50 lb under generous spacing and a long warm season. Color at the principal harvest or mature stage: Red. Sweet, juicy, old-fashioned red watermelon flavor.
Saving seed
Seed saving for Black Diamond Select several healthy, true-to-type plants so the saved lot represents the variety rather than one unusually early or large individual. Melons are insect-pollinated and varieties of the same species can cross. Isolate compatible varieties or use controlled pollination, and mark fruit from healthy true-to-type plants. Allow seed fruit to become fully ripe; eating ripeness and seed maturity should both be reached. Remove seed, separate pulp by washing or short fermentation as appropriate, rinse until clean, and dry in a thin layer with good airflow. Keep records of species, variety, plant count, isolation, ripeness test, fruit traits, and year.
Common problems
Watch Black Diamond for cucumber beetles, squash bugs where applicable, aphids, powdery or downy mildew, bacterial wilt, crown rot, poor pollination, and fruit damage on wet soil. Rotate cucurbit crops, provide airflow, water at the root zone, protect young plants before flowering, and remove covers when blossoms need pollinators. Do not work wet vines.
Frequently asked questions
When is Black Diamond ready?
80-89 Days from warm direct sowing or equivalent established transplant
How long does germination take?
Expect 5-10 Days near 75–90 °F; actual emergence changes with moisture, seed condition, and soil temperature.
How large does it grow?
About 97–120 in with a vining/climbing habit. Support: No-Support.
Can it grow in a container?
Best in open ground or a large raised bed; mature vines require substantial horizontal or vertical space.
How is it used?
Primary uses: large gardens, family gatherings, market displays, and growers who want an imposing heirloom watermelon. Sweet, juicy, old-fashioned red watermelon flavor.
Can I save seed?
Yes where the crop biology allows, but keep compatible varieties isolated, use several healthy plants, wait for full seed maturity, dry thoroughly, and label the lot.
Minimum Seed Count:30 seeds
