Black Diamond Watermelon Seeds

Black Diamond watermelon is a late-season watermelon developed in Arkansas in the 1940s by seed expert Melville Dillon and it became popular in the 1950s via seed catalogues and word of mouth. The plants are easy to grow and quite productive, suiting both rookie home gardeners and market growers.

Heirloom Black Diamond watermelon is known as a giant variety. The slightly oblong melons measure about 12-14 inches wide and weigh 30-40 pounds, but they can reach 100 pounds or even more in perfect conditions! The flesh is bright red and juicy, with high sugar content and the striated dark blue-green rind is sufficiently thick to provide good resistance to bruising. The spreading vines have large leaves that help prevent sunburn, and they can reach 15 to 20 feet across, so prepare your garden accordingly. If started indoors four to six weeks prior to the last frost in your area, the fruits can start producing in mid-season, perfect timing for refreshing summer treats!

- Latin Name: Citrullus lanatus
- Life Cycle: Annual
- Days to Maturity: 90
- Planting Depth: 2-3 cm
- Plant Spacing: 60 cm or 30 cm with trellis
- Row Spacing: 1.5-1.8 m
- Growth Habit: Short-vine spreading

GROWING INSTRUCTIONS

In the blazing heat of a summer afternoon, what’s more quenching than enjoying a juicy, sweet slice of watermelon? Watermelon for sure is more prevalent in warmer climates, but growers in cold regions can have success starting seeds indoors. This summertime gem will need plenty of sun and space, but can easily be started from seed. From the day of planting it can take up to 100 days to harvest, depending on the variety.

Start seeds 2-3 weeks before the last frost date. Plant into separate pots, about 1 cm deep. Use slightly larger pots than usual  to accommodate expansive root growth. Or, compostable pots may be a good option. They can be transplanted directly with little disturbance to the roots. If kept moist  and at a warm temperature seeds should germinate within a few days. Provide plenty of light for the first few weeks.

When soil reaches at least 18°C, prepare to harden off and transplant. Watermelons tend to need an abundance of nutrients in order to produce their enormous fruits. So, prepare the bed beforehand with plenty of compost. Make sure this site receives full sun, has loose, well-drained soil and that vines will have plenty of space to spread. Transplant very carefully, roots are fragile and can be damaged easily. Either plant in traditional rows about 2 m apart, or in 1.5 m wide mounds, 60-90 cm apart.

Provide young plants with 3-5 cm of water/week until fruit are set. Reduce water at that point to promote the production of sweet fruit. Add mulch to retain moisture and provide a dry resting place for fruit as it matures.

Be good to your pollinators! Male and female flowers are produced and need healthy native insects to aid in fertilization.

To tell if a watermelon is ripe. Give it a slap! Hollow sounding melons should be ready. If the underside is a cream or yellow color, that is a good indicator of maturity. Finally, check the stem where it is attached to the fruit. If it is still green, wait. Once it starts to die off, or is dead, the fruit should be ready to pick. Snip the stem with clippers or a knife close to the fruit.

Watermelon is an essential sweet treat that every gardener should grow to help beat the summer heat!

QUICK FACTS

- The first evidence of watermelon cultivation is in Ancient Egypt, where they were cultivated for their high water content and stored to be eaten during dry seasons. During the seventh century, watermelons were cultivated in India, by the 10th century had reached China, and by the 17th century, were widely planted in Europe.

- Watermelon seeds will remain viable for 4 years if stored in a cool, dark place, ideally between 4 and 10⁰C. After that, the germination rate may start to go down.