The following was posted previously on What About Watermelon, but it’s a fascinating topic, so I’ve decided to post it again. Enjoy!

Let’s get one thing out of the way right up front: It doesn’t matter what shape the watermelon is, it’s what’s inside that matters. That said, you have to admit there’s something cool about watermelons that defy convention by assuming different shapes.

Last month, I talked about Japanese farmers who had figured out a way to grow heart-shaped watermelons. Of course, the precursor to those sweethearts are the unusual square watermelons that got their start in Japan almost a decade ago. But how are they grown, and why bother tampering with Mother Nature? Both are good questions. I’m glad I asked them.

First, the how. It’s actually pretty easy (relatively speaking) to grow a square watermelon. Just about anyone can do it. While the watermelon is still small on the vine, a square, tempered glass box is placed around it. When the watermelon gets bigger, it assumes the shape of the box! You can do this too. There are even websites dedicated to teaching you how. Just remember to use a glass or transparent mold so the sunlight can reach the watermelon on all sides (except the bottom, I guess).

And why are square watermelons grown? Two reasons actually. First, the square watermelons are easier to stack, which makes them easier to ship. Second, and perhaps most ingeniously, with space being an issue in crowded areas of Japan, the square watermelon is designed to fit perfectly inside smaller Japanese refrigerators.

But, just like the heart-shaped creations, square watermelons cost a bit more than one shaped by Mother Nature. It’s a small price to pay for the ability to store it in your fridge, although I guess you could just cut up a normal watermelon and make it fit. Oh well… the square ones still look pretty darn cool.


  1. David Smouse says:

    Amazing, but how do they taste ?

  2. marla Johnson says:

    what a great idea! Havent heard of it before. Also i would think as it grows, it would have to be placed in larger & larger containers, but maybe not.Maybe once the shape is formed early on, it continues to grow in that shape. Would like to know for curiosity’s sake. I also would like to know where I can one of these!

  3. Jim Long says:

    I can remember years ago going to an old barber shop in the country and the barber had a full size watermelon in a glass gallon jug on his counter and it always mistified me as to how he got that melon in the jar without breaking the glass. I sat still the whole time my hair was being cut trying to figure that out. After I got older i found out the melon after it started to blossom was put in the gallon jar to grow and after it filled the jar it was clipped and filled with white vinegar. I miss those old days.

  4. Frannie says:

    I always thought they looked really cool, but did wonder why they were shaped that way. I would still go for the big, circular shaped watermelons because that means more for me to eat!

  5. The Watermelon Guy says:

    I’d imagine they taste the same as the regular ones, but it’s hard to say for sure.

    Jim – That melon-in-a-jar sounds really cool. I’m going to try to find a picture of something like that online!

  6. Bill says:

    On the news this morning they had a clip on square watermelons grown in Japan. They were not only expensive, about a $100 each bit they were not edible. So then why grow them and even more important, why pay so much for one, they said they were used for display, whatever that meant they didn’t elaborate but sounds stupid to me. As tight as space is in Japan one would think they would use their infinity on growing food for the masses.

  7. says:


    The square watermelons, despite the video, are edible. Just like any crop, you will have some that are picked prematurely and are not, but there’s no “curse” preventing someone growing a square watermelon and letting it ripen.

    Cinagro Farms in California and others have done this domestically with great success.

    We sell the molds to farmers and individual growers( Some do it for the novelty, some to get children interested in growing, and some do it for advertising purposes.

    Many, if not all, of the people have heard about Heart and Square shaped watermelon through social media. Jim Long (above) mentioned a memory he had from his childhood and a barber.

    These extremely out of the ordinary fruits generate a lot of conversation and publicity. Some companies will spend thousands of dollars for the exposure and “word of mouth” a square pumpkin or watermelon can generate just by being on a counter somewhere.

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