How Do You Know When A Watermelon Is Done Growing

You know a watermelon is done growing when the tendril closest to the fruit turns brown and dries up completely.
 
That little curly tendril is nature’s built-in timer, and once it shrivels, the melon has stopped expanding.
 
At that point, no amount of water, fertilizer, or patience will make it any bigger, so it’s time to focus on ripening instead of growing.
 
If you’ve been staring at your patch wondering how do you know when a watermelon is done growing, this guide will walk you through every sign to look for.
 
We’ll cover the tendril trick, the thump test, field spots, and more so you can pick at the perfect moment.
 
Let’s get into it.
 

How Do You Know When a Watermelon Is Done Growing?

A watermelon is done growing once it reaches full size and its external cues shift from growth to ripening.
 
Here are the clearest signs that your watermelon has finished growing.
 

1. The Nearest Tendril Turns Brown

The tendril that grows right next to the fruit’s stem is the most reliable indicator.
 
While the melon is still growing, that tendril stays green and pliable.
 
When growth stops, the tendril dries out and turns brown, which tells you the watermelon is done growing.
 
This happens because the plant shifts its energy from sizing up the fruit to ripening it.
 

2. The Skin Loses Its Shine

A growing watermelon has a glossy, almost waxy surface that reflects light.
 
Once it’s done growing, that shine fades into a dull, matte finish.
 
If you rub your hand across the rind and it feels smooth but not slick, that’s a good sign the watermelon has stopped growing.
 

3. The Field Spot Turns Creamy Yellow

Flip the watermelon over and check the spot where it rested on the ground.
 
While it’s growing, that spot looks pale white or light green.
 
When the watermelon is done growing, the field spot deepens into a creamy yellow or even orange hue.
 
The darker the color, the longer it sat ripening on the vine.
 

4. The Thump Sounds Hollow

Give the watermelon a firm thump with your knuckles.
 
A watermelon that’s still growing sounds dense and dull, almost like you’re hitting a wall.
 
Once it’s done growing, the sound shifts to a deep, hollow thump.
 
That hollow echo means the flesh inside has filled with water and sugar, and the fruit has stopped expanding.
 

5. The Weight Feels Heavy for Its Size

Pick up the watermelon and compare its weight to its size.
 
A watermelon that’s done growing feels heavy, like it’s packed with liquid.
 
If it feels light for its size, it either stopped growing too early or it’s drying out inside.
 
Heaviness is one of the best ways to tell when a watermelon is done growing because it signals maximum water content.
 

How Long Does It Take for a Watermelon to Finish Growing?

Most watermelons take 80 to 100 days from planting to reach full size.
 
Once the fruit sets, it grows rapidly for about 30 to 50 days.
 
After that, the watermelon is done growing and enters the ripening phase, which lasts another 10 to 14 days.
 
So if you’re counting days, mark the calendar when you first see a tiny melon appear.
 
That’s your starting point for tracking when the watermelon will be done growing and ready to pick.
 

What Happens If You Pick a Watermelon Before It’s Done Growing?

If you harvest too early, the watermelon won’t ripen any further off the vine.
 
Unlike tomatoes or bananas, watermelons don’t continue ripening once they’re cut.
 
So picking before the watermelon is done growing means you’ll end up with pale, bland, and sometimes crunchy flesh.
 
That’s why it’s so important to wait for the tendril to brown and the other signs to appear before you grab your knife.
 

Can You Speed Up the Growing Process?

You can’t force a watermelon to finish growing faster than nature allows.
 
But you can help it along by keeping the soil consistently moist, not soaked.
 
Give the plant plenty of sunlight and avoid over-fertilizing with nitrogen late in the season.
 
Too much nitrogen keeps the vine producing leaves instead of finishing the fruit, which delays when the watermelon is done growing.
 

Should You Turn the Watermelon While It Grows?

Some gardeners rotate their watermelons to encourage even ripening.
 
But once the watermelon is done growing, turning it can damage the field spot and confuse your ripening cues.
 
Leave it alone in the final stretch and let it rest on the same side it grew on.
 

So, How Do You Know When a Watermelon Is Done Growing?

You know a watermelon is done growing when the nearest tendril turns brown, the skin dulls, the field spot yellows, and the thump sounds hollow.
 
Those signs together tell you the fruit has reached its full size.
 
Once a watermelon is done growing, it won’t get any bigger, so all that’s left is letting it ripen on the vine.
 
Wait for those cues, and you’ll pick a watermelon that’s sweet, juicy, and ready for the table.