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You know black diamond watermelons are ready when the tendril closest to the fruit has dried up and turned brown.
That’s the biggest signal, but it’s not the only one.
If you’ve been staring at your black diamond watermelon wondering when to pick it, you’re in the right place.
Black diamond watermelons don’t ripen much after you pick them, so knowing exactly when they’re ready matters a lot.
Pick too early and you get pale, bland flesh that’s more rind than reward.
Pick too late and the melon turns mealy and mushy inside.
In this post, we’ll cover how to know when black diamond watermelons are ready, the signs to look for, and the mistakes to avoid.
Let’s dive in.
How to Know When Black Diamond Watermelons Are Ready
Learning how to tell when black diamond watermelons are ready comes down to a few reliable signs.
Black diamond watermelons are a large, dark green heirloom variety with a thick rind and sweet red flesh, and they take about 85 to 95 days to mature.
Here’s what to look for when you’re checking if your black diamond watermelons are ready to harvest.
1. The Tendril Dries Up
This is the number one sign that black diamond watermelons are ready.
Look for the small, curly tendril growing on the vine right next to where the stem connects to the fruit.
When that tendril is green, your black diamond watermelon is still growing and not ready yet.
When it dries up and turns brown, that’s your green light.
This single sign is more reliable than almost anything else when it comes to knowing when black diamond watermelons are ripe.
2. The Ground Spot Turns Creamy Yellow
Flip your black diamond watermelon over and check the spot where it rests on the ground.
On an unripe melon, that spot looks white or pale green.
On a ripe black diamond watermelon, it turns a rich, creamy yellow.
If the spot is still white, give it more time.
This ground spot is one of the easiest ways to tell when black diamond watermelons are ready without cutting them open.
3. The Rind Loses Its Shine
A young black diamond watermelon has a glossy, shiny rind.
As it ripens, that shine fades and the rind takes on a dull, matte look.
Run your hand across the surface and compare it to younger melons on the vine.
When your black diamond watermelon looks dull instead of glossy, it’s getting close.
4. The Thump Test
Give your black diamond watermelon a firm thump with your knuckles.
A ripe melon makes a deep, hollow sound, almost like a drum.
An unripe black diamond watermelon sounds flat and dull.
An overripe one sounds mushy and muffled.
The thump test works best once you’ve already seen the dried tendril and creamy ground spot, so use it to confirm what you already suspect.
Other Signs Black Diamond Watermelons Are Ready
Beyond the main signs, there are a few extra clues that black diamond watermelons are ready to pick.
1. The Stem Starts to Dry
The stem connecting your black diamond watermelon to the vine begins to shrivel and brown as the fruit ripens.
It won’t dry completely like the tendril, but you’ll notice it losing that fresh green color.
When the stem starts to dry, your black diamond watermelon is nearly ready.
2. The Skin Feels Tough
Press your thumbnail into the rind of your black diamond watermelon.
If it dents easily, the melon isn’t ready yet.
If the rind feels hard and resists your nail, that black diamond watermelon is ripe and ready for harvest.
3. It Gets Heavy
Ripe black diamond watermelons feel heavy for their size because they’re packed with water and sugar.
Pick up a few melons and compare their weight.
The heaviest black diamond watermelon in the patch is usually the ripest one.
4. The Vine Starts Dying Back
As the season winds down, the vine feeding your black diamond watermelon starts to yellow and die back.
When the vine near the fruit begins to wither, that’s a strong hint that your black diamond watermelon is ready.
Mistakes to Avoid When Harvesting Black Diamond Watermelons
Even when you think you know when black diamond watermelons are ready, a few common mistakes can trip you up.
1. Picking Based on Size Alone
Big doesn’t always mean ripe.
Black diamond watermelons can reach 30 to 50 pounds, but a huge melon can still be underripe inside.
Always check the tendril and ground spot before you decide your black diamond watermelon is ready.
2. Waiting Too Long
Once your black diamond watermelon is ripe, it won’t stay perfect forever.
Overripe black diamond watermelons turn grainy, mushy, and bland.
Check your patch every day once you see the first signs, and harvest as soon as your black diamond watermelon is ready.
3. Yanking the Melon Off the Vine
When your black diamond watermelon is ready, cut the stem cleanly with a knife or pruners instead of pulling.
Leave about an inch of stem attached, since this helps the melon store longer.
4. Ignoring the Weather
Too much rain right before harvest can water down the flavor of your black diamond watermelon.
If heavy rain is coming and your black diamond watermelons are ready, go ahead and pick them.
So, How Do You Know When Black Diamond Watermelons Are Ready?
You know black diamond watermelons are ready when the tendril next to the fruit dries up, the ground spot turns creamy yellow, the rind loses its shine, and a good thump gives you that deep hollow sound.
Black diamond watermelons don’t ripen after picking, so nailing the timing is everything.
Use the signs above, check your patch daily once harvest season hits, and you’ll never second-guess a black diamond watermelon again.
Here’s to sweet, juicy slices all summer long.