How to Grow Seedless Watermelons Successfully

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Seedless watermelons are a summertime favorite for their crisp, juicy flesh and near-absence of tough black seeds. If you’ve ever wondered how to grow seedless watermelon in your home garden, it’s important to understand how these special melons work—and why they require a little extra planning.

I’ve grown seedless watermelon in my own garden in Sonoma Valley, where long, warm summers make the effort worthwhile. With a little know-how and the right setup, you can enjoy your own harvest of nearly seed-free melons.

What Are Seedless Watermelons?

Despite the name, seedless watermelons aren’t truly seedless—they contain small, soft, often translucent white seeds that are edible and barely noticeable. These are triploid watermelons, meaning they have three sets of chromosomes (compared to the two sets in standard “diploid” melons).

Triploid seedless watermelons are created by crossing a diploid watermelon with a tetraploid one (four sets of chromosomes). The result is a plant that produces fruit but cannot reproduce itself—so it won’t form viable seeds unless pollinated by a regular seeded watermelon.

Pollination: The Key to Growing Seedless Melons

Because seedless watermelon plants are sterile, they must be grown alongside a pollinator variety (a seeded watermelon) to produce fruit. That means you need two types of watermelon in your garden: the seedless type you want to eat and a compatible seeded variety to provide pollen.

Most seedless watermelon seed packets for home gardeners include seeds for a pollinator plant. For successful pollination:

• Plant both types at the same time.
• Alternate plants in the row or nearby.
• Make sure bees and other pollinators have access.

In my experience, spacing pollinator plants every third or fourth plant in the row works well.

How to Plant Seedless Watermelons

Here’s what I recommend for growing seedless watermelons successfully:

1. Start Seeds Indoors

Seedless watermelon seeds can be slow and finicky to germinate. I start mine indoors 2–3 weeks before transplanting:

• Keep soil temperatures around 85°F (29°C).
• Use peat pots or soil blocks to avoid disturbing roots at transplant.
• Harden off seedlings before moving outdoors.

2. Choose a Sunny Location

Watermelons need full sun and warm soil—at least 70°F (21°C). Prepare beds with well-drained soil, enriched with compost or aged manure.

3. Transplant Carefully

Transplant seedlings once nighttime temperatures stay above 60°F (15°C). Space plants 3–4 feet apart in rows 6–8 feet apart. For small gardens, try growing on mounds or in raised beds with trellis support.

4. Ensure Strong Pollination

Pollination is essential. Without it, your seedless melons won’t form at all. Here’s what helps:

• Grow plenty of flowers (like sunflowers or zinnias) nearby to attract bees.
• Avoid pesticides during flowering.
• Plant the included pollinator seeds early and near the seedless varieties.

Water and Feed for Maximum Sweetness

Keep seedless watermelons evenly moist while they’re growing, but cut back watering a bit as fruit matures to concentrate sugars.

Fertilize regularly:

• Early growth: Use a balanced fertilizer like 10-10-10.
• Once vines run: Switch to a low-nitrogen, higher phosphorus/potassium fertilizer to promote flowering and fruiting.

When to Harvest

Seedless watermelons are ready for harvest 80 to 90 days after transplanting, depending on the variety. Here’s how to tell they’re ripe:

• The underside of the melon turns creamy yellow.
• The tendril nearest the fruit stem dries and turns brown.
• The rind changes from shiny to dull.

In my garden, I mark transplant dates on a calendar and start checking melons around 75 days.

Best Seedless Varieties for Home Gardeners

Some seedless watermelon varieties I’ve grown and recommend:

• Triple Crown Hybrid – Very sweet and crisp, 80 days.
• Summer Sweet 5244 – Uniform, deep red flesh, 84 days.
• Queen of Hearts – Round, dark green rind with bright red interior, 85 days.

Choose a variety with a maturity date that fits your climate’s warm season.

Conclusion

Growing seedless watermelon requires more planning than growing traditional melons, but the payoff is worth it. With the right seed selection, pollination support, and care, you’ll enjoy the convenience of crisp, nearly seed-free slices from your own garden. In my experience, the extra steps are well worth the reward.

Comparison of Popular Seedless Watermelon Varieties