How to Tell If a Watermelon Is Ripe?

When to Harvest Watermelon

Sep 10, 2018
Watermelon Harvest

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Every year I am faced with the same dilemma: how to tell if a watermelon is ripe. Muskmelons are easy; they will slip right off the vine at the peak of perfection. However, watermelons remain firmly attached even when they are overripe.

I am no good at the “thump” test. Old-timers swear that they know when a watermelon is ripe just by rapping it with a knuckle. If the sound is low-pitched, hollow, and deep like a drum it is ready. Johnny’s Seed Company explains further to say that it should sound like “punk” rather than “pink” or “pank” when you flick it with your finger. I have failed miserably at this test in years past, picking unripe melons that are still white inside. Once they are detached from the vine watermelons won’t continue to ripen. You only get one chance to do this right.

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When all else fails I guess I should look at the seed packet. It says that my Sugar Babies should be ripe in 80 days from planting and though we started the seeds indoors in early May they did not get planted in the garden until early June. I think they should be ready any day now but since they do most of their ripening in the last 2 weeks of growth, it is important not to jump the gun.

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Tricks to Tell if a Watermelon is Ripe

Here are other subtle cues to look out for:

  • The green color becomes dull.
  • On a striped melons, the color between the stripes gets darker.
  • The rind will get hard.
  • The blossom end will soften.
  • They will stop getting larger.
  • The ground spot will turn from white to yellow.

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My Sugar Babies don’t have a ground spot.

  • The end of the main vine nearest the fruit may start to crack or turn brown.
  • The curly tendril on the main vine, closest to the fruit, will turn brown.

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Curly tendril is still green!

Do you have any tried and true method of determining the ripeness of a watermelon that you’d like to share?

See more about harvest watermelons on the Almanac’s Watermelon Growing Guide.

 

An update:

The curly tendril finally dried up last week and here is the result - a perfectly ripe watermelon!

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About This Blog

Get inspired by Robin Sweetser's backyard gardening tips. Robin has been a contributor to The Old Farmer's Almanac and the All-Seasons Garden Guide for many years. She and her partner Tom have a small greenhouse business and also sell plants, cut flowers, and vegetables at their local Farmer's Market.

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I know some people have told

I know some people have told me in crazy, but I try to use what my grandmother taught me. Broom straw. Get a piece of broom straw that is as straight and possible and find a pet well rounded spot on your melon, lay the piece of straw on that spot and gently let it go. If your melon is ripe the straw will actually spin, it may not spin like a helicopter blade but it will turn on its own. I have only ever tried this in the grocery store to check melon's for ripeness but I'm sure it will work in the garden and well.

How to tell if the watermelon is ripe

Years ago there was an article in "Organic Gardening" on how to tell ripeness. The tip that works for me is first make sure it is not shinny, next I feel around the melon for ridges. Any fruit that gets numerous seeds in a row will bulge where the seeds are after they are mature. Of course if it is seedless this might not work.

Testing watermelons for ripeness

I used to grow watermelons commercially. I found that each variety has different 'signals' as to when it's ripe. The most common was the yellow belly. Some had the first small leaf on the vine closest to the attachment point dry up as an indicator. Others it was the curly tendril that dried up.

I most often used the sound when the melon was thumped to guide me. It's all in the tone and is very hard to teach to others. I tried with my brightest worker, but he never got the knack of it. When he picked the watermelons, I got complaints. So I went back to thumping and marking the ones to pull. Interestingly Desert King, a yellow meated melon, would have a tone all its own. Much lower and more dull than other melons. You had to learn the variety's own code.

Cantaloupes were easier for the workers to pick. The outside would lose its green cast and with very gentle pressure the melon would detach from the vine - called 'full slip'. What you see in the super markets these days are cantaloupes with a piece of the vine still attached. Don't even bother. They taste like cardboard. As a backup, smell the vine end of the melon. It will smell like cantaloupe.

Honeydew melons will be soft on the blossom end when pushed. The softer, the more ripe until it's overripe. Yellow skinned honeydews are easier to pick. They don't turn yellow until they are close to ripe.

Watermelon ripeness test

Pressing the melon on top and listening to the inside crunch works quite well.

watermelons

There is no substitute for the thump test. Once you've heard the sound of a ripe melon, it will forever be unmistakeable (unless you have a tin ear). I am a city boy gone seaside yankee and I had to learn many years ago incity markets how to pick a good melon or grandma would never forgive me. An old man at a farmers market showed me what to look for and I've never been wrong since. We eat watermelons like a main course around here and buy several a week during season.

watermelons ripening

My dad was a farmer, and he grew just about everything, he always said when the bottom of a melon is yellow, then its ripe. He didn't grow the sugar babies so not sure about them. Thank you, Susan Reynolds

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