Spring planting doesn’t start when the air feels warm, It...Read More
Black Diamond Watermelon is characterized by a remarkably dark, nearly black-green rind, creating a stark and eye-catching contrast with the vibrant red flesh inside. Notably, this variety is renowned for its significant size, often achieving impressive weights, often reaching 30 to 40lbs, however there are records of this variety weighing up to 80lb! The Black Diamond Watermelon plant boasts vigorous vines that sprawl across the garden, along with large, deeply lobed dark green leaves that enhance its overall lush and robust appearance. This variety is particularly well-suited for warm climates, thriving in environments with abundant sunlight and well-draining soil. As the watermelon reaches peak ripeness, the rind undergoes a noticeable transformation, losing its initial sheen and deepening in color.
NAME: Watermelon (Citrullus lanatus)
VARIETY: Black Diamond
DAYS TO MATURITY: 80 – 90 days
POLLINATION: Open Pollinated
TYPE: Annual
HARDINESS ZONE: Zones 3 – 12
SUNLIGHT: Full Sun
SOIL: Fertile, loose soil with a pH 5.5 – 6.5
PLANT HEIGHT: 12 – 16 inches
SPACING: 36 – 48 inches apart
TEMP: 55 – 95°F
These seeds do not required stratification.
To learn more about Stratification, click here!
Start seeds indoors 1 week before your last local frost.
Sow 2 to 3 seeds 1/2 inch deep in each large cell in your cell tray or in 4 inch pots that have proper seed starting mix; water in gently. Provide a heated area or heat mats to keep the soil at least 75°F. Germination should occur in 7-14 days.
Supply fluorescent/LED grow lights 3 inches above the cells or pots, 12 hours on, 12 hours of.
Keep the soil moist until seedlings sprout and germination will occur in 4 to 9 days.
Thin to one seedling per cell as soon as the first set of true leaves appear.
Transplant seedlings outdoors a week after your last local spring frost and after soil temps are above 60°F; plant them 2 feet apart in rows spaced 6 feet apart.
Do not disturb roots when transplanting, and water thoroughly.
Once soil temps are 60°F you can begin direct sowing seeds outdoors.
Form raised soil patches that are 1 foot in diameter, raised up 5 inches with soil/compost, spaced 3 feet apart; sow 2 to 3 seeds 1/2 inch deep, in each of these patches.
Keep moist and germination will occur within 7-14 days.
As these warm season plants grow, they will produce male and female flowers; pinch back some of the flowers to help keep a consistent energy distribution flowing throughout the vines to get large fruits
Prepare your planting beds by picking a spot that gets full sun and has loose, fertile soil with a pH of 5.5 – 6.5, removing any surrounding weeds and adding ample compost.
In cool climates, Black Diamond Sweet watermelon seeds should be started indoors.
As soon as the vines begin to develop, apply a thick layer of mulch to control weeds and protect the watermelons from soil contact.
Keep the soil moist until the fruit begins to grow, then water only if the soil dries out completely; do not water the last week before fruits are ripe, as overwatering can cause bland fruit.
Black Diamond Watermelons are ready for harvest when the tendrils near the stem begin to dry out and turn brown, and the underside of the melon changes from green to yellow, which usually takes around 90 days.
Use a sharp knife or shears to cut the melon from the vine, leaving a few inches of stem attached.
Store harvested watermelons in a cool, dry place or refrigerate them for up to two weeks.
