What you see: Holes inside your watermelon.
What it is: The flesh is disintegrating.
Eat or toss: If it smells normal, then sample it and see how you feel about it; it’s probably overripe and may be soft, mealy and taste oddly squash-like. If it smells funky, and is slimy or foamy, some microbial invaders may be at play and your best bet is to toss.
Can you eat a watermelon with holes inside?
If a melon with holes inside like this otherwise looks OK (without obvious slime or foaming) and doesn’t smell off, then go ahead and try it. It has higher odds of tasting overripe and unappealing, but if it tastes good enough for you, then it’s fine to eat.
What causes holes in watermelon?
Once you rule out microbial growth, holes like these in a watermelon could have developed over time as the melon grew overripe, or formed rapidly with exposure to ethylene, a plant hormone that accelerates aging. Even traveling on a truck with tomatoes, famous for emitting ethylene, could have been enough to shrink a watermelon’s period of peak ripeness. Ethylene basically attacks cell walls, which causes them to disintegrate, explained Penelope Perkins-Veazie, a professor of horticultural sciences at North Carolina State University.
Why would overripening cause holes inside a watermelon?
Over time, a watermelon starts to break down from within–it’s all part of the plan since at the end of the day a watermelon is a living, respiring entity that will run out of resources. It’s also designed to spread its seeds, so when the melon breaks down it gets its seeds closer to the soil where they hope to sprout. So the watermelon’s cells collapse. When large, juicy watermelon cells collapse it can look like portions of the fruit have simply disappeared.
The watermelon featured at the top of this post is seedless, but you can see how the holes have formed where the seeds would have been. Perkins-Veazie told me that the cavities around those would-be seeds are the first to succumb to stress; they’re where hormones shift first and are particularly sensitive.
Is a watermelon with holes inside safe to eat?
First, just rule out the possibility of infection. Large wounds or soft spots on the exterior and a clear path of destruction indicate an invading microbial force. It is also possible for microbes to more surrepticiously slip into melons in the slightly less secure spot where they used to be attached to the vine (experts suggest harvesting watermelons with about 2 inches of stem still attached). In that case you might not see a wound on the exterior, but you may spot some clues: maybe odor, foaming or fizzing. If the right cocktail of microbes assembles inside, they can literally stage a fermentation party in which carbon dioxide builds up and things might even culminate with an exploding melon. Flying watermelon chunks or not, you definitely don’t want to eat a watermelon that’s being colonized by microbes. As for the image at the top of this post, there were no signs of fungal or bacterial activity, phew.
Why do older watermelons taste off?
Perkins-Veazie noted that watermelons’ red color comes from the pigment lycopene.
But like their squash cousins, watermelons also contain beta carotene, which is orange and responsible for giving butternut squash its hue. When beta carotene breaks down during the natural aging process, it tastes so intensely squashy as to be off putting to some people. I am one of those people, as is Perkins-Veazie.
“Some people would enjoy it,” she said. “But I’d be running in the other direction, because I can’t stand the squash flavor in a watermelon.”
Truth: Once this past summer I cut into a slightly mealy watermelon that I found tasted nearly inedible. But there was no evidence of microbial growth, my four year old seemed fine with it, and so I, with apologies, offered some to a friend. She said it tasted just fine to her. So, tolerance of older watermelons really can come down to personal taste.
Does a watermelon with holes around the seeds have hollow heart?
No, the widening holes around the seeds in this watermelon are different from the gaping cracks caused by the condition known as hollow heart. Hollow heart, which also leaves the melon still edible, but possibly with reduced quality, is caused by pollination problems and not overripening.
SOURCES:
- Penelope Perkins-Veazie. Horticulture professor. North Carolina State University.
- Watermelon (Oregon Vegetables). Oregon State University. College of Agricultural Sciences, Department of Horticulture.
- Watermelon. Produce Fact Sheets. Postharvest Research and Extension Center. University of California.
- Watermelon. Iowa State University Extension and Outreach. Richard Jauron Dan Fillius Aaron Steil. Last reviewed: August 2023. Referenced November 2024.
