Black Diamond Watermelon | Complete Guide to Grow and Care | Expert Opinion

Black Diamond Watermelons are named for their glossy, solid black-green rind. However, the flesh is cherry-red. The flesh is always tender and sweet, with 25 to 40 grayish-black seeds. It requires a long, warm growing season. It is a great variety, like Charleston gray watermelon and crimson sweet watermelon.

Features and Properties of Black Diamond Watermelons

The following table shows the features and properties

Scientific Name	Citrullus lanatus
Common Name	Black Diamond Watermelon
Family	Cucurbitaceae
Native Area	Africa
Plant Type	Annual / Spreading, creepy, vine, can spread in length up to 20 feet
Leaves	Slow releasing Potash and Nitrogen fertilizers
SK Units	119000 SKU
Appearance	Black-green rind, cherry red flesh
Light requirement	Grow well after frost in full sun
Average Weight	35 to 50 pounds (lbs)
Days to maturity/ When to harvest	Time to maturity is about 90 days
Plant spacing	7-8 feet
Planting Time	After frost days, in Spring and summer
Row spacing	16-18 inches
Soil	Well-drained with slightly acidic soil (pH 6.0)
Water / Irrigation	Frequent irrigation (after each 5-7 days)
Fertilizers	Add compost, well-rotten FYM, or Seaweed
Organic Amendments	Add compost, well-rotten FYM or Seaweed
Number of Seeds per fruit	More than 25
Nutrition Values	Vitamin C, Beta-Carotene,  Lycopene
Importance and Uses	Used as Dessert (cholesterol free)
Hardiness Zones	Used as Dessert (cholesterol-free)

How to Grow Black Diamond Watermelon from Seeds?

Please follow the following expert opinions for planting and getting well-juicy melons.

Time to Grow

Early spring is the best planting time for these melons in the home garden and indoors. At maturity, they require heat. Thus, growing these in early spring will require 1.5 to 2 months of good warmth to get them perfectly ripe.

However, if you are in the North and want to enjoy farm-fresh black diamonds, you can grow these in the plastic mulch covering warm soil in the greenhouses. This mulch and greenhouse will trap air and keep the soil and atmosphere comparatively warm. The perfect time for growing Black Diamonds in the North is when peonies bloom. It is usually 2 weeks after the last frost. Sowing will be more than 80% successful in early summer when the temperature is 70°F

Sowing Methods

Consider the following cares

• Soil should be well-drained.
• Sow it ½ inches deep in the soil after the last frost in the well–drained garden soil.
• Space seeds and rows at 3-5 feet as the plant is creepy and spreading in nature. Thus, give them proper room for it. They can spread up to 20 feet in radius.
• Indoor sowing can be done 3-4 weeks earlier in a controlled environment.
• Keep plant-to-plant distance as low as 18” with rows 5-8 feet apart.
• Apply frequent irrigation as the plant is not drought-resistant.
• Frequent irrigation is also recommended to get juicy and sweet flesh.
• It is nutrient intensive, requiring the release of Nitrogen and potassium.

Use the humidity dome and seed trays where the weather is cold and frost is still around. Plant seeds in trays and shift in the field when the temperature is more than 70°F.

Flowers and Fruiting

It is monoecious, with both male and female flowers growing on the same plant. However, the male flower blooms earlier and dies. Female flowers bloom 2-3 weeks after the male flower. It has a small swelling at the base, indicating fruit initiation. The flowers are open-pollinated and require bees for successful pollination. If the weather is rainy during flowering, this may restrict the free movement of bees and other pollinators.

Harvesting and Storage

I have experience storing melons for 1-2 weeks without a refrigerator. However, a cool storage room will increase the storage time. If you have extra melons, cut them, make dice or balls, and freeze them for later usage.

Plant Cares

Plant of black diamond requires the following cares

• Optimum Temperature – Sowing must be done after the frost when the temperature is more than 70°F.
• Light – They perform well in early to mid-summer with plenty of sunlight.
• Thinning – To maintain a plant-to-plant distance of 8 feet, thinning of the plant is done after 2 weeks of sowing.
• Frequent Irrigation – The plant is drought-sensitive, so frequent irrigations are applied. Better to use sprinkler irrigation
• Soaker Hose – to avoid over-watering, use a soaker hose to hold extra water. This will also help in preventing fungal diseases.
• Irrigation in the early morning – Apply water early in the morning so that excess water can evaporate in the sun.
• Control Weeds – Control weeds earlier in the growing season as it would be difficult to move around when the vines spread.
• Fertilizers and Nutrients – Apply premium quality fertilizers. It is better to use granular fertilizer for slow release. Apply more nitrogen-based fertilizers at the early growing stage while applying potash and phosphorus-based fertilizers at maturity.
• Straw Beds – Keep all the maturing watermelons on the straw beds to avoid direct contact with the soil. Cardboard can also serve the same purpose here, but it will not be economical.
• Aluminum Foil – Use it to concentrate heat and light to speed up the ripening and maturity.
• Baskets upside down – keep your ripened fruit safe from critters (hogs) by covering the fruits with weighted-down laundry baskets.
• Diseases – Plant faces fungal attacks (Alternaria, Anthracnose, Blight Spots). Downy mildew (yellow or pale green) and powdery mildew (white powder, spots) are common in moist environments. Apply Fungicides after consulting extension services.
• Insects – Aphid attack is common. Check the underside of the leaves frequently. Apply insecticidal soap. If there is an attack of beetles, apply rotenone (pyrethrum-based insecticide) to kill these beetles. However, never use broad-spectrum insecticides as they may kill bees (pollinators).
• Trellising – It is not recommended as the fruit is as heavy as 50 pounds

Conclusion

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