Chow Line: Watermelon tasty, nutritious

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My favorite fruit is watermelon. Since it’s so watery, does it offer much nutrition?

You’re correct that watermelon is “watery.” In fact, it’s more than 90 percent water. Still, two cups of diced watermelon (about 10 ounces) offers 38 percent of the vitamin C you need in a day, 32 percent of vitamin A, as well as a small amount of protein and fiber, and all for a mere 85 calories.

Watermelon is also a good source of lycopene, a phytonutrient that gives your favorite fruit (as well as tomatoes and pink grapefruit) its red color. Lycopene protects against prostate cancer and possibly other cancers, and also protects cells from damage associated with heart disease.

In addition, citrulline in watermelon is converted into arginine, an amino acid that plays a key role in cell division, wound healing, and the removal of ammonia in the body.

Watermelon also offers some potassium, which is helpful because most Americans don’t get enough of it. Potassium helps control blood pressure and possibly prevent strokes.

Part of the challenge with watermelon is choosing one that’s ripe. That’s not always easy to figure out, according to “Selecting, Storing and Serving Ohio Melons” ( from Ohio State University Extension. Here are some suggestions from the fact sheet:

  • Examine the rind and find the spot where the melon had been resting on the ground — it should be yellow-white. If it’s white or pale green, it was picked too early.
  • Scratch the surface of the rind with your thumbnail. If the outer layer slips back with little resistance showing the green-white under the rind, the watermelon is ripe. If all you get is a darker depressed line, the melon isn’t ripe.
  • When purchasing cut watermelon, look for more red flesh and less white rind to find riper melons. White seeds usually indicate the melon was picked too early — unless you’re looking at a seedless watermelon. In that case, any white seeds you see are really just empty seed coats.

If you think your watermelon isn’t quite ripe yet, keep it at room temperature for a few days. It will continue to ripen if it’s not too mature. But only whole, uncut watermelon should be left unrefrigerated. Once it’s cut, watermelon needs to be kept at 40 degrees F or below.

Before cutting into watermelon (or any melon), be sure to thoroughly rinse it under clean running water. You may even want to scrub it with a soft-bristled brush while rinsing. This will help remove any contaminants on the rind that could spread to the fruit inside when you slice through it.

Chow Line is a service of Ohio State University’s College of Food, Agricultural, and Environmental Sciences and its outreach and research arms, Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or

Editor: This column was reviewed by Dan Remley, field specialist in Food, Nutrition and Wellness for Ohio State University Extension, the outreach arm of the College of Food, Agricultural, and Environmental Sciences.

For a PDF of this column, please click here.

CFAES News Team
For more information, contact: 

Dan Remley
OSU Extension, Food, Nutrition and Wellness