How Long Have Seedless Watermelons Been Around

Seedless watermelons have been around since the 1940s, when a Japanese scientist first figured out how to make them.
 
That’s right—these sweet, spit-free fruits aren’t a modern lab experiment from the 2000s.
 
They actually have a pretty long history that most people never hear about.
 
If you’ve ever wondered how long seedless watermelons have been around, you’re in the right place.
 
In this post, we’ll dig into the origins of seedless watermelons, how they’re made, and why they’ve been around for far longer than you might think.
 
Let’s get into it.
 

How Long Have Seedless Watermelons Been Around?

Seedless watermelons have been around for more than 80 years, with their roots tracing back to 1939.
 
That’s when a Japanese plant breeder named Kihara made a breakthrough.
 
He discovered that by crossing a diploid watermelon (the normal kind with seeds) with a tetraploid watermelon (a type with double the chromosomes), he could create a triploid seed.
 
The triploid seeds grow into plants that produce fruit with tiny, white, undeveloped seeds—what we now call seedless watermelons.
 
So the next time you bite into a seedless watermelon, remember you’re enjoying a piece of history that’s been around since before World War II.
 

1. The 1930s Breakthrough in Japan

The story of how long seedless watermelons have been around starts in Japan in the late 1930s.
 
Kihara was studying watermelon genetics when he figured out how to manipulate chromosome counts.
 
By treating watermelon seeds with a chemical called colchicine, he could double the chromosome number, creating tetraploid plants.
 
When those tetraploid plants were crossed with regular diploid plants, the resulting seeds were triploid—and those triploid seeds produced seedless fruit.
 
This was a game-changer, and it laid the foundation for every seedless watermelon we eat today.
 

2. Seedless Watermelons Arrived in the U.S. in the 1950s

While seedless watermelons have been around since the 1940s in Japan, they didn’t make their way to American farms until the 1950s.
 
Researchers at the University of California and other agricultural stations started experimenting with triploid watermelons after the war.
 
By the 1960s, seedless watermelons were being grown commercially in the United States, though they were still a niche product.
 
It took a few more decades for them to become the everyday grocery store staple we know today.
 

3. Why They Took Decades to Catch On

Even though seedless watermelons have been around for over 80 years, they didn’t become popular overnight.
 
The main reason is that growing them is trickier than growing regular watermelons.
 
Triploid seeds have a lower germination rate, and the plants need to be pollinated by a diploid variety to produce fruit.
 
Farmers also had to figure out the best growing conditions and convince consumers that a watermelon without seeds was actually a good thing.
 
By the 1990s and early 2000s, improvements in breeding and farming techniques made seedless watermelons more reliable and affordable.
 
That’s when they really started to dominate the market.
 

How Are Seedless Watermelons Made?

Now that you know how long seedless watermelons have been around, let’s talk about how they’re actually made.
 
It’s not genetic engineering—it’s good old-fashioned plant breeding.
 
Here’s the basic process:
 

1. Creating Tetraploid Parent Plants

First, breeders treat regular watermelon seeds with colchicine, a natural chemical that doubles the chromosomes.
 
This creates tetraploid plants, which have four sets of chromosomes instead of two.
 
These plants produce larger seeds and flowers but aren’t the ones you eat.
 
They’re just one half of the equation.
 

2. Crossing Tetraploids with Diploids

Next, the tetraploid plants are crossed with normal diploid watermelons.
 
The result is a triploid seed, which has three sets of chromosomes.
 
Triploid seeds grow into plants that produce seedless watermelons.
 
The seeds inside the fruit are tiny, white, and soft—so soft you can eat them without even noticing.
 

3. The Role of Pollinators

Here’s the catch: triploid watermelon plants are sterile.
 
They can’t pollinate themselves, so farmers have to plant regular diploid watermelons nearby.
 
Bees then carry pollen from the diploid plants to the triploid flowers, which triggers fruit development.
 
Without those pollinators and companion plants, you wouldn’t get any seedless watermelons at all.
 

Why Seedless Watermelons Are So Popular Today

Seedless watermelons have been around for decades, but their popularity has skyrocketed in recent years.
 
Part of it is convenience—no seeds means no spitting, no choking hazards for kids, and easier slicing.
 
Part of it is taste—seedless varieties have been bred to be sweeter and crisper than many seeded types.
 
And part of it is marketing—grocery stores love them because they’re easier to eat and less messy.
 
Today, seedless watermelons make up the majority of watermelons sold in the United States.
 
So even though they’ve been around since the 1940s, they’ve only recently become the default choice for most shoppers.
 

1. They’re Not Actually 100% Seedless

Here’s a fun fact: seedless watermelons aren’t truly seedless.
 
They have those tiny white seeds we mentioned earlier.
 
They’re just so soft and undeveloped that you barely notice them.
 
So technically, seedless watermelons have been around with those little seeds all along—they’re just not the hard, black seeds you’d spit out.
 

2. They’re Grown All Over the World

Today, seedless watermelons are grown in the U.S., Mexico, Brazil, China, and many other countries.
 
Since they’ve been around for so long, farmers have had plenty of time to perfect their growing techniques.
 
That’s why you can find them year-round in most supermarkets, even in the middle of winter.
 

So, How Long Have Seedless Watermelons Been Around?

Seedless watermelons have been around since the 1940s, when a Japanese scientist named Kihara created the first triploid watermelon.
 
They made their way to the U.S. in the 1950s, became more common in the 1990s, and now dominate the market.
 
So the next time you enjoy a slice of seedless watermelon, you’re tasting a fruit with a history that spans more than eight decades.
 
Not bad for something that started as a lab experiment.