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You can grow black watermelon by choosing the right variety and giving it plenty of sunshine, warmth, and room to sprawl.
Black watermelon isn’t a different species from regular watermelon, it’s just a type that develops a very dark green rind that looks almost black when ripe.
And if you’ve been wondering how to grow black watermelon in your own backyard, the good news is that the process is pretty similar to growing any other watermelon.
The main difference is that black watermelon varieties often need a bit more heat and a longer growing season to reach that deep, glossy color.
In this post, we’ll walk through how to grow black watermelon step by step, from picking seeds to harvesting a sweet, ripe fruit.
Let’s dig in.
How to Grow Black Watermelon From Seed
Growing black watermelon starts with good seeds and a warm start.
Here’s how to get it right from the beginning.
1. Pick the Right Black Watermelon Variety
The first step in how to grow black watermelon is choosing a variety known for that dark rind.
Popular options include Black Diamond, Sugar Baby, and Charleston Gray, all of which can develop that deep, almost-black skin under the right conditions.
Black Diamond is a classic choice if you want a large, oblong fruit with dark green skin.
Sugar Baby is smaller and rounder, and it ripens a little faster, which makes it great for shorter growing seasons.
2. Start Seeds Indoors or Direct Sow
Black watermelon seeds need warm soil to germinate, ideally around 70 to 90°F.
If your growing season is short, start the seeds indoors about three to four weeks before the last frost date.
Use peat pots or biodegradable trays so you can transplant without disturbing the roots.
If you live in a warm climate, you can direct sow black watermelon seeds right into the garden once the soil has warmed up.
3. Give Them Full Sun and Plenty of Space
Black watermelon plants are vines, and they love to spread out.
Choose a spot that gets at least eight hours of direct sunlight every day.
Space your plants about three to five feet apart in rows that are six to eight feet apart.
Good airflow and room to grow help prevent disease and give those heavy fruits space to develop.
How to Care for Black Watermelon as It Grows
Once your black watermelon is in the ground, the real work begins.
Here’s how to keep it healthy and productive.
1. Water Deeply but Not Too Often
Black watermelon needs consistent moisture, especially while the fruit is swelling.
Water deeply once or twice a week, aiming for about an inch of water each time.
Avoid overhead watering late in the day, since wet leaves can invite fungal problems.
A drip irrigation system or soaker hose is ideal for keeping the soil moist without soaking the foliage.
2. Feed With the Right Nutrients
Black watermelon is a heavy feeder, so it benefits from rich, well-drained soil.
Mix in compost or aged manure before planting, and side-dress with a balanced fertilizer once the vines start running.
Once flowers appear, switch to a fertilizer lower in nitrogen and higher in phosphorus and potassium to support fruit development.
Too much nitrogen will give you lots of leaves but very few melons.
3. Watch for Pests and Diseases
Like all watermelons, black watermelon can attract aphids, squash bugs, and cucumber beetles.
Keep an eye on the undersides of leaves and remove pests by hand or with a gentle insecticidal soap.
Powdery mildew and fusarium wilt are common problems, so rotate your crops and avoid planting where you’ve grown melons before.
How to Tell When Black Watermelon Is Ripe
Knowing when to harvest black watermelon can be tricky because the rind is so dark.
Here are a few signs to look for.
1. Check the Field Spot
The field spot is the patch where the melon rested on the ground.
On a ripe black watermelon, this spot turns from white to a creamy yellow or orange color.
If it’s still bright white, the fruit probably needs more time.
2. Listen for the Thump
Give the black watermelon a gentle thump with your knuckles.
A ripe melon will sound deep and hollow, while an unripe one sounds dull and flat.
This trick works especially well once you’ve practiced on a few melons.
3. Look at the Tendril and Stem
The curly tendril closest to the fruit will dry up and turn brown when the black watermelon is ready.
The stem itself starts to shrink and pull away slightly from the vine.
Once you see these signs, it’s time to harvest.
So, How Do You Grow Black Watermelon?
You grow black watermelon by starting with the right variety, giving it full sun and warm soil, watering deeply, and feeding it well throughout the season.
Black watermelon isn’t harder to grow than any other melon, it just needs patience and a little extra heat to reach that signature dark rind.
Pick a sunny spot, keep the soil rich and moist, watch for pests, and harvest when the field spot turns yellow and the thump sounds hollow.
With a bit of care, you’ll be slicing into your own homegrown black watermelon before you know it.