This post contains affiliate links. As an Amazon Associate I earn from qualifying purchases. If you click a link and make a purchase, I may receive a small commission at no extra cost to you.
You can grow black watermelon by choosing a dark-rind or dark-flesh variety, giving it full sun, and letting the fruit mature fully on the vine.
If you’ve been wondering how to grow black watermelon, the good news is that it’s not much harder than growing regular watermelon.
The “black” look usually comes from a very dark green rind that looks almost black, or from a variety with deep red to near-black flesh.
Either way, the growing process is basically the same as any other watermelon.
In this post, we’ll walk through how to grow black watermelon from seed to harvest, including variety picks, planting tips, and the mistakes that trip most people up.
Let’s dig in.
How to Grow Black Watermelon: The Basics
Growing black watermelon starts with understanding what you’re actually planting.
1. Pick the Right “Black” Variety
There’s no single species called black watermelon.
Instead, “black watermelon” refers to cultivars bred for an unusually dark appearance.
Popular choices include Black Diamond, which has a nearly black rind and sweet red flesh.
Other options like Dark Belle and Sugar Baby (when fully mature) also develop a deep, dark rind.
If you want black flesh, look for heirloom types with names like Black Spanish or certain Asian varieties sold as “black seed” melons.
Order seeds from a reputable supplier so you know exactly what you’re growing.
2. Give It Full Sun and Warmth
Black watermelon loves heat.
Plant it somewhere that gets at least 8 hours of direct sunlight every day.
Watermelons are tropical by nature, so cold soil will stall them fast.
Wait until soil temperatures stay above 70°F (21°C) before planting.
If you’re in a cooler climate, start seeds indoors about three weeks before your last frost date.
3. Prepare Rich, Well-Draining Soil
Watermelons feed heavily, so amend your soil with compost or aged manure before planting.
Aim for a pH between 6.0 and 6.8.
Good drainage matters too, because soggy roots lead to rot and weak vines.
Raised beds or hills work great for growing black watermelon in most gardens.
Planting and Caring for Black Watermelon
Once your conditions are right, the rest is mostly about consistent care.
1. Space Plants Properly
Watermelon vines spread far, so give each plant room to breathe.
Space them 3 to 5 feet apart in rows that are 6 to 8 feet apart.
Crowding invites disease and reduces airflow, which black watermelon hates.
If space is tight, grow a smaller variety up a sturdy trellis.
2. Water Deeply but Not Too Often
Watermelons need about 1 to 2 inches of water per week.
Water deeply at the base so the roots grow strong and deep.
Avoid overhead watering, since wet leaves encourage mildew.
Once fruit starts ripening, cut back slightly to concentrate sugars.
3. Feed With the Right Nutrients
Use a balanced fertilizer early on to support leafy growth.
Switch to a lower-nitrogen blend once flowers appear.
Too much nitrogen gives you giant vines and tiny fruit.
Side-dress with compost or a potassium-rich fertilizer when the melons begin to swell.
4. Pollinate and Protect
Black watermelon needs bees to set fruit.
Plant flowers nearby to attract pollinators, or hand-pollinate if bee activity is low.
Use row covers early to block pests, then remove them when flowers open.
Watch for aphids, squash bugs, and powdery mildew throughout the season.
Harvesting Black Watermelon
Knowing when to pick is the trickiest part of growing black watermelon.
1. Watch the Tendril
The curly tendril closest to the fruit turns brown and dries up when the melon is ripe.
This is one of the most reliable signs.
2. Check the Field Spot
The spot where the melon rested on the ground should turn creamy yellow or pale orange.
If it’s still white or green, give it more time.
3. Listen for the Thump
A ripe black watermelon gives a deep, hollow thud when you knock on it.
A dull thump usually means it’s underripe.
4. Look at the Rind
The rind should look dull rather than shiny, and the dark color should be fully developed.
Once picked, black watermelon won’t ripen further, so timing really counts.
So, How Do You Grow Black Watermelon?
You grow black watermelon by picking a dark variety, planting it in warm, sunny, well-drained soil, and giving it steady water and nutrients all season.
While the name sounds exotic, growing black watermelon follows the same rhythm as any other watermelon.
Start with quality seeds, keep the vines healthy, and harvest at the right moment.
Do that, and you’ll be slicing into a stunning, sweet black watermelon before you know it.