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How to Grow Seedless Watermelon Seeds?

When I heard about growing seedless Watermelon from seeds, I could not comprehend what it meant.

I wondered, “How would you grow seedless Watermelons from seed if there are no seeds?”

After scouring the internet, I understood the puzzling details of growing seedless Watermelon.

In general, to grow seedless Watermelon seeds, scrape the coat slightly, soak the seeds in water and sow them about 2 to 4 inches deep in well-draining loose soil. Ensure to maintain the temperature above 75° during germination and transplant the seedlings after they grow over 6 to 9 inches.

watermelon
Growing Seedless Watermelons from seeds is a complex task and demands passion for plants.

Even if growing seedless Watermelon from seeds is a bit sensitive and difficult, it is definitely worth your passion and dedication.

Therefore, continue reading so you can overcome the complex hurdles of growing seedless Watermelons.

Overview of Seedless Watermelon Seeds

The mystery and desire to devour seedless Watermelon finally came true when professor Hitoshi Kihara devised a method to make one in 1939.

He was a Japanese scientist at Kyoto University who later commercialized seedless Watermelon in 1951.

Professor H. Kihara tweaked the chromosome counts of normal Watermelon to create a seedless hybrid variety of Watermelon.

He crossbred between normal Watermelons and tetraploid Watermelons to make a seedless hybrid of Watermelons. 

seeds of seedless watermelon
With proper care, seedless Watermelon seeds will germinate within two weeks.

Here is a quick overview of the seed of seedless Watermelon to get you acquainted.

Seed AttributesProperties
ShapeElliptical seeds
ColorDark brown, black
SizeAround 1-1.5 cm in length with thicker coat than that of normal Watermelons.
Weight5-15 seeds per gram
Germination InitiatorWater
Germination Time7 to 14 days
Germination TemperatureAt 85°F through out the germination process and after 40% growth maintain temperature at 70-80°F
Treatment Prior To Germination1. Scarring the seed coat
2. Soaking in warm water for almost 24 hours.
3. Dry them properly before sowing them.
Soil Type and pH For Seed GerminationWell-draining, sterile soil with pH between 6.0 and 6.8.
Seed Sowing Depth4 inches deep
ToxicityNon-toxic for pets and humans

Many gardeners often get confused when they hear about growing seedless Watermelon from seeds.

Growing seedless Watermelons through seeds sounds crazy, right?

Where do Seedless Watermelon Seeds Come from?

Seedless Watermelon results from the complex crossbreeding between diploid Watermelons and tetraploid Watermelons.

I know it is bamboozling, so just understand it involves various chemicals and processes to perform crossbreeding.

Therefore, seedless Watermelon is not a genetically modified food (GMO).

watermelon seedling
The triploid Watermelon is infertile, making it seedless.

Generally, normal Watermelons have 11 pairs (2X) of chromosomes, while the seedless has 11 triploids (3X) chromosomes.

And that is why seedless Watermelons are known as triploid Watermelons.

Meanwhile, there are no seeds in triploid Watermelons because they are infertile. So, they can not make seeds.

If you are having difficulty understanding this, just take the example of mules.

They are the hybrid cross between horse and donkey and are sterile, meaning they cannot reproduce.

Similarly, the triploid is infertile, making it a Watermelon with no seeds.

seedless watermelon
Seedless watermelons come from a cross between the hybrid of diploid and tetraploid watermelons.

Seedless Watermelons do not occur naturally in nature and need intense, costly steps to develop.

Generally, seedless Watermelon seeds can cost you around 150$ for just 100 seeds.

Furthermore, you can expect the worst while germinating these expensive seeds because they have a very low germination rate.

How to Get Seedless Watermelon Seeds?

Watermelon plants are dioecious, meaning they have separate male and female flowers.

Meanwhile, female flowers of tetraploids are the ones that form fruit after cross-pollination with diploid Watermelon.

Therefore, you will have to plant tetraploid and diploid Watermelons together to get seedless Watermelon seeds.

flower of watermelon
Watermelon plants are dioecious. So, they have separate male and female flowers.

In general, the female flowers of Watermelon has tiny melon on their back, while male flowers do not.

Meanwhile, male flowers of tetraploid won’t make fruits with female diploid flowers.

To efficiently produce the triploid Watermelons, you must hand pollinate the flowers.

Here are a few steps to properly hand pollinate.

  • Find a cotton swab or paintbrush and carefully select the flowers that have matured and are ready for pollination.
  • Collect pollens by rubbing the paintbrush or cotton swab on the flower’s anthers.
  • Place the pollens on the female flowers properly.
  • Repeat these steps as many times as you feel like doing.
  • Within a month, you will be able to notice ripening Watermelon fruit with seedless Watermelon seeds in it.

Watch the video to hand pollinate the Watermelon flowers properly,

Seedless Watermelon Seeds for Sale

Many scammers all over the internet claim to provide seedless Watermelon seeds.

Therefore, you have to be careful when buying seeds of seedless Watermelon.

Here I have included some certified stores with seedless Watermelon seeds for sale.

SellersShipping
Johnny's Selected SeedsShipping may take at least 3-10 business days
SeedwayWithin 2 weeks delivery
Harris SeedsShips within 1-2 business days of receipt
Urban FarmerWithin 1-2 business days
Gurney's Seed & Nursery Co.Shipping may take at least 3-5 days

How to Grow Seedless Watermelon Seeds?

As I mentioned earlier, the germination of seedless Watermelon seeds is not an easy task.

Even if you provide ideal, conducive conditions for your seeds, they have a low germination success rate.

However, you can enjoy juicy Watermelon that won’t have any seeds upon successful germination.

watermelon seeds
Seedless Watermelon seeds have a low germination rate.

Meanwhile, you have two different methods to plant seedless Watermelon seeds. They are direct sowing and transplanting.

However, the transplanting method is much better and suitable for Watermelon.

But before getting your hands dirty, gather around these materials.

Materials RequiredPurpose
SeedsFor germinating
Seed Starter MixFor growing the seeds
Seed TrayPotting Medium
Gloves
For safety
Plastic bag or sheetTo maintain humidity and temperature for the seeds
2-3" PotCeramic, Clay, or Plastic pot with drainage holes for transplantation

Now, let us begin this rather delicate journey of planting seedless Watermelon seeds, shall we?

Step 1: Prepare the Seed

The viability of the seeds is greatly influenced by their harvesting time. So, ensure to check the quality of the seeds and are new ones before buying one.

After getting fresh new seeds, follow the seed prep steps.

  • Presoak the seeds in a cup filled with lukewarm water for almost a day.
  • Ensure the seeds are completely dry before sowing them.
  • Try scrapping the rounded end of the seed to encourage faster germination, allowing better water uptake.

Step 2: Prepare the Starter Mix

You can use a light seed starter sterile mix with good aeration and better water drainage.

Before sowing the seeds in the soil, ensure you thoroughly soak the potting mix and let it dry for almost 24 hours.

Starter soil mix
Presoak the potting mix properly before sowing the seeds.

I highly suggest you buy readymade sterile potting soil from certified retailers rather than making it yourself.

Because seedless Watermelon seeds are very sensitive to soil saturation, you might not be able to maintain the quality that the seeds prefer.

Step 3: Sow the Seeds

Before filling the germination tray with potting mix, sterilize them properly.

  • Fill in the germination tray with potting mix leaving behind 1/4th part of the tray empty.
  • You can add pebbles or gravel at the bottom of the tray to encourage better drainage.
  • If the surrounding and soil temperature is less than 75°F, place a heating pad below the tray to make a minimum soil temperature of 75°F.
  • Make a hole by poking your finger or chopstick in almost 2 to 4-inch depth soil.
  • Place the seedless Watermelon seeds in it and gently cover it up with a potting mix.
  • For direct sowing, maintain 12 inches distance between each seed when planting.
  • Afterward, you can prepare a mini greenhouse using clear plastic to maintain ideal humidity and soil.
  • Maintain the conducive temperature for the seed at 75°F to 85°F.
  • Carefully water the soil to keep it moist and humid with the help of a mister.

Voila! Within two or four weeks, you will be able to see brand-new seedlings shooting from the seeds of seedless Watermelons.

Step 4: Transplant the Seedlings

After the successful germination of the seeds embraced with ideal care and affection, it is time to transplant them.

Once seedless Watermelon seedlings grow over 6 to 9 inches and consist of a true set of leaves, they are ready to go wild in your garden.

But ensure the garden soil temperature is above 70°F and avoid transplanting before summer.

Due to the high sensitivity of triploid seeds to cold injury, you can use plastic mulch to keep the soil temperature intact.

watermelon seedling
Take care of your Watermelon seedlings and transplant them outside once the outside temperature is warm for Watermelon to grow.

Meanwhile, you must plant other normal Watermelon plants next to each other.

The pollens produced by seedless Watermelon are sterile. Therefore, a plant needs other plants’ fertile pollens for fruiting.

For efficient cross-pollination, plant seedless Watermelons and normal Watermelons in an alternate fashion.

You shall plant at least one pollinator Watermelon for two triploid Watermelon plants.

When planting pollinator Watermelon, you shall choose a distinct one to recognize seedless with seeded Watermelon at the time of harvest.

Have patience and wait for about 100 days so that you can devour the juicy seedless Watermelon.

Do not worry! Here is an article to help you out with the perfect timing to harvest Watermelons.

Tips to Care for Seedless Watermelon After Planting

The seedlings of seedless Watermelons are sensitive to various care factors, so it is mandatory to provide them care even after transplanting.

Here are some basic care requirements for your new seedless Watermelon seedings.

CareSpecification
Sunlight1. Provide at least 6-8 hours of full sunlight or partial shade.

2. Avoid low-light areas as it discourages no blooms or fruits.
Temperature1. Provide 70°F or above temperature during spring and summer.

2. The saplings prefer a consistent 65°F during the day and 60°F
at night.
Humidity1. Maintain a moderately higher humidity level of 50 to 60%.

2. Regular misting will help achieve moderate humidity.
Watering1. Provide water to your plant on a daily basis till it starts fruiting.

2. Let the top few inches of the soil dry out between watering
after the fruit appears.

3. Provide 1/2 inch of water per week to keep the soil moist but
not soggy.
Fertilization1. Use fertilizer with NPK 5-10-10 to feed the plant for proper growth.

2. Avoid fertilizing immediately after blossoming to avoid problems.

Conclusion

Seedless Watermelon is a result of a complicated crossbred process between two different Watermelons.

Like its complex nature, growing seedless Watermelon from seeds is also difficult and sensitive.

Regardless of the slim chances of successful germination, they are still rewarding when provided the best care and efforts.

Happy Gardening!

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