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Black diamond watermelons are known for their enormous size and juicy, sweet flesh.
This late-season heirloom variety is popular for home gardens, and large, commercial farms.
The dark, blue-green-black melons have rich red flesh.
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and typically lack the usual stripes of more familiarwatermelon varieties.
Covering the soil with black plastic before seeding helps warm up the soil.
Selecting a Planting Site
Watermelonsneed a location in full sun with well-draining, rich soil.
When direct seeding, plant some extra seeds in between.
When plants are 3 inches tall, thin them out.
Trellising is not recommended due to the heavy weight of the fruit.
Soil
Black diamond watermelons enjoy soil rich in organic material.
They prefer neutral to slightly acidic, warm, moist, well-draining soil mediums.
A layer of organic mulch such as straw underneath the vines and fruits will help retain soil moisture.
Keep the soil moist, but not soggy.
Around two weeks before the fruit is ripe, stop watering to increase the sugar content in the fruits.
Temperature and Humidity
These melons prefer hot temperatures and do not handle cold well.
They prefer moist conditions, though very high humidity can cause fungal problems.
Fertilizer
Black diamond watermelons do well in rich soil with organic material.
Amending the soil with plenty of compost before planting will ensure these melons receive the necessary nutrients.
Fertilizer can be applied when flowers appear to help encourage healthy fruit production.
For amounts to use and program instructions, consult the fertilizer product label.
Pollination
Watermelons have male and female flowers on each vine which need pollination to produce fruit.
double-check you have planted flowering plants nearby that attract nectar-collecting bees, which are the primary pollinators of watermelons.
Don’t use broad-spectrum insecticides, as they indiscriminately kill pests and pollinating insects.
Before harvesting fruits and their seeds, look forsigns that the melons are ripe.
Check the tendrils where the melons connect to the plant.
Check the rind of the melon.
Keep only the seeds that sink to the bottom of the bowl and toss out the ones that float.
Pruning
Only watermelons grown on a trellis require pruning to control excessive vine growth.
The heavy black diamond watermelons are unsuitable for trellising so there is no need to prune the vines.
Biodegradable pots work best because watermelons don’t like their roots disturbed.
Avoid planting melons in an area where plants of the cucurbit or squash family were grown the previous year.
These watermelons are enormous and weigh 50 pounds or more.
Their flesh is sweet and juicy yet crisp and with a slight tanginess.
Black diamond watermelons are heirloom watermelons.
The black diamond watermelon was developed in the 1940s by seed expert Melville Dillon.
