How Are Square Watermelons Grown

Square watermelons are grown by placing the developing fruit inside a sturdy, rigid box while it’s still small on the vine.
 
The watermelon then grows into the shape of the box, resulting in that famous cube look you see in fancy grocery stores.
 
If you’ve ever wondered how are square watermelons grown, the answer is simpler than you might think, though it does take patience and careful timing.
 
Growers in Japan actually pioneered this technique back in the 1980s as a way to make watermelons easier to stack and store.
 
In this post, we’ll walk through exactly how square watermelons are grown, the tools you need, and why they cost so much more than regular melons.
 

How Square Watermelons Are Grown

Square watermelons are grown by using a mold, and here’s how the process actually works.
 

1. Start With a Young Watermelon on the Vine

The process of growing square watermelons begins when the fruit is still tiny, usually about the size of a golf ball or a small fist.
 
Growers wait for a watermelon to set on the vine and then carefully select one that looks healthy and uniform.
 
This timing is critical because once the watermelon starts expanding, it needs to be placed in the mold before it gets too big to fit.
 

2. Place the Fruit Inside a Rigid Mold

The grower then slides the young watermelon into a box-shaped mold, typically made of clear plastic, glass, or sometimes wood.
 
These molds are usually cube-shaped and have enough internal space for the watermelon to fill out completely.
 
The mold stays on the vine with the watermelon inside, often supported so it doesn’t fall or shift as the fruit grows heavier.
 

3. Let the Watermelon Grow and Fill the Space

As the watermelon matures, it naturally expands and presses against the inner walls of the mold.
 
Since the mold is rigid, the watermelon has no choice but to take on its shape, which is how square watermelons get their distinctive form.
 
This stage takes several weeks, and growers monitor the fruit closely to make sure it isn’t cracking or developing soft spots.
 

4. Harvest at the Right Time

Once the watermelon has filled out the mold and reached maturity, it’s harvested by cutting it from the vine.
 
The mold is then removed, revealing a perfectly square watermelon that’s ready for market.
 

Why Square Watermelons Are So Expensive

Square watermelons cost way more than regular ones, and there are a few reasons why.
 

1. Labor-Intensive Growing Process

Growing square watermelons requires far more hands-on work than growing regular watermelons.
 
Each fruit has to be individually placed in a mold, monitored, and eventually removed by hand.
 
That’s a lot of manual labor for a single melon, and it drives the price up significantly.
 

2. Higher Failure Rates

Not every watermelon grown in a mold turns out perfectly square.
 
Some crack under the pressure, some develop uneven shapes, and others simply don’t fill out the mold properly.
 
Growers have to discard these imperfect fruits, which means the successful ones carry the cost of the failures.
 

3. Limited Growing Regions

Square watermelons are grown mostly in specific regions, with Japan being the most famous producer.
 
The climate and expertise required to grow them successfully aren’t available everywhere.
 
This limited supply, combined with high demand from luxury markets, keeps prices sky-high.
 

Can You Grow Square Watermelons at Home?

You can grow square watermelons at home if you’re willing to put in the effort.
 

1. Get the Right Mold

You’ll need a sturdy, cube-shaped mold that can hold up as the watermelon expands.
 
Many gardeners use clear plastic boxes or specially designed watermelon molds sold online.
 

2. Timing Is Everything

Place the mold on the watermelon when it’s still small, usually a few days after the flower pollinates.
 
If you wait too long, the watermelon won’t fit inside without damage.
 

3. Provide Support and Shade

Molds can get heavy as the watermelon grows, so support them with bricks or a small stand.
 
Also, keep the mold shaded to prevent overheating, which can cook the fruit inside.
 

So, How Are Square Watermelons Grown?

Square watermelons are grown by placing young fruit inside rigid, cube-shaped molds while they’re still on the vine.
 
The watermelon expands into the shape of the mold, and once it’s mature, it’s harvested and the mold is removed.
 
It’s a time-consuming, labor-intensive process, which is why square watermelons are more of a luxury item than an everyday fruit.
 
But if you’re curious and patient, you can try growing square watermelons in your own garden.
 
Whether you buy one at a specialty store or grow one yourself, now you know exactly how square watermelons are grown.