Is Seedless Watermelon GMO?

Last year I came across a square watermelon. Yes, I said a square watermelon! That, of course, prompted this inquiring mind to look into that phenomenon further. Are square watermelons GMO? You can read all about my findings in “Wanna Make Some Money? Grow Square Watermelons!

With the bounty of regularly shaped watermelon making frequent appearances at picnics and cookouts this time of year, my 6 year old with a look of confusion, asked me how seedless watermelons can even grow without a seed to plant. “What a great question,” I thought! One that needed further exploring…

According to the National Watermelon Promotion Board, only 16 percent of watermelons sold in grocery stores have seeds – down from 42 percent in 2003.

I fondly remember backyard seed spitting contests, or screeching in horror as my grandfather would swallow the seeds from each chomp of his watermelon, laughing about the watermelon that would grow in his stomach. Nowadays, our kids, don’t even identify with the iconic black dotted, pink watermelon slice! Rather a slice of watermelon to them looks like the ones above! 


Are There Any Benefits to Eating Seeded, Unadulterated Watermelon?

Watermelon is originally native to the East Indies and Africa and has long been used medicinally. In fact, the seeds were believed to be effective in the treatment of worms and urinary infections. Making a tea by simmering the seeds in water for 30 minutes was traditionally used as a natural remedy for kidney and bladder problems. The watermelon flesh is high in lycopene and has high levels of vitamins A and C and a good level of vitamin B6, but those seeds sure sound like they play a heck of a role! 


So, Why Did the Watermelon Become Seedless?

As with most everything in our culture of convenience, the seeds in watermelon apparently were and are an inconvenience. Those pesky seeds cause us to have to pause to spit them out (input sarcasm). With an increase in people on the go, seedless watermelon is in high demand partly because of the desire to consume watermelon in quick fruit salads that can be purchased and eaten on the run. All you have to do is head into a Whole Foods and check out their selection of cut and packaged fruit to understand, AND as we all know, demand influences supply.


How Did the First Seedless Watermelon Come About?

The first seedless watermelon came about over 50 years ago. It was created by cross-pollinating 2 watermelon varieties, each of which has differing numbers of chromosomes. In order to produce a seedless watermelon, a diploid watermelon (with 2 sets of 11 chromosomes) is cross-bred with a tetraploid watermelon (4 sets of chromosomes). The result is a sterile watermelon that contains 3 sets of chromosomes which makes them sterile. These sterile watermelons (AKA triploids) produce tiny white seeds that are actually ‘seed coats’ from a seed that did not mature. Breeders call it the mule of the watermelon world.


…And How is it done today?

Nowadays there are two options when growing a seedless watermelon:

  1. The crossbreeding method as mentioned above.
  2. The use of a chemical called colchicine – This chemical alters the chromosomes in the watermelon seeds from 2 to 4. It is applied once the seedling emerges from the soil to stop the natural chromosome division. To be effective it must be applied twice daily for 3 days (yuck!).


So, Does That Make Seedless Watermelons GMO?

In the broadest sense of the words, there could be an argument that the humble watermelon was genetically altered, however, it is not officially considered GMO because no genetic material from any other species was introduced. If you’re a purest you will definitely want to stay away from the seedless watermelon.

If you’re concerned about your health, you may just want to think twice before eating that next juicy slice of seedless melon.

NOTE: Because they are not labeled, you will never know if colchicine was involved in the growing of your melon.


Where can I buy an Old Fashioned Seeded Watermelon?

Just an FYI, by far the largest world producers of the seedless watermelon is China, followed by Turkey, Iran, the USA, and Egypt. If you’re looking for a classic melon, look no further than your local farmer’s market. A juicy organic, seeded watermelon is not only nostalgic but nourishing as well!




The Healthy Food Directory by Michael Van Straten

The Washington Post

NC State Horticultural Science

North Carolina State University