How to Grow Watermelons From Seeds

Ever bitten into a slice of watermelon on a hot summer day and thought, “I wish I could grow this myself”? Good news: you can—and it’s easier than you might think! Growing watermelons from seeds is a fun, rewarding gardening project that anyone with a sunny spot and a little patience can take on.

Nothing says summer quite like biting into a juicy, sweet slice of watermelon fresh from your garden. Growing watermelons from seeds might seem daunting at first, but with the right steps, anyone can enjoy this rewarding experience. Whether you have a sprawling backyard or a cozy garden patch, this guide will walk you through everything you need to know to turn tiny seeds into luscious fruits.

Why Grow Watermelons From Seeds?

Sure, you can buy seedlings from the garden center—but starting from seeds gives you more control over varieties, ensures healthier root systems, and can even save you money. Plus, watching your watermelon plants sprout and thrive from tiny seeds is incredibly satisfying.

Choose the Right Watermelon Variety

Before planting, decide what type of watermelon you want to grow. Here are a few popular choices:

• Sugar Baby – Small, sweet, and ideal for small spaces.
• Crimson Sweet – Classic variety with striped skin and juicy red flesh.
• Charleston Gray – Long, gray-green melons with a high sugar content.
• Yellow Flesh Black Diamond – Offers a unique, sweet yellow flesh.

Want to grow other types of melons too? Check out our complete guide on how to grow melons from seed for tips that work across cantaloupes, honeydews, and more.

Tip: Check your USDA hardiness zone and choose a variety that thrives in your local climate. Most watermelon varieties need a long, warm growing season (at least 75–90 days).

When to Plant Watermelon Seeds

Watermelons are warm-weather crops that hate the cold. Plant seeds outdoors only after the last frost date in your area, and when soil temperatures are consistently above 70°F (21°C). If your growing season is short, start seeds indoors 3–4 weeks before transplanting.

Pro tip: Use biodegradable pots to avoid transplant shock when moving seedlings to the garden.

How to Plant Watermelon Seeds

1. Choose a sunny location
   Watermelons need at least 6–8 hours of full sun each day.
2. Prepare the soil
   Watermelons love loose, well-draining, nutrient-rich soil. Mix in compost or aged manure for extra fertility. Aim for a pH between 6.0 and 6.8.
3. Plant in mounds
   Mound the soil into small hills about 12 inches high and 2 feet wide. This helps with drainage and warms the soil faster.
4. Sow the seeds
   Plant 2–3 seeds per hill, about 1 inch deep. Space the mounds 3 to 5 feet apart, depending on the variety.
5. Thin the seedlings
   Once the seedlings emerge, thin to the strongest plant per hill to give it room to grow.

Watering and Care Tips

Watermelons are made up of over 90% water, so consistent watering is key, especially during flowering and fruiting.

• Water deeply once or twice a week rather than daily. Aim for about 1–2 inches of water weekly.
• Avoid overhead watering. Water at the base to reduce the risk of fungal diseases.
• Mulch around the plants to retain moisture, regulate temperature, and suppress weeds.

Feeding Your Watermelons

Hungry plants make sweet fruits. Fertilize your plants:

• Early growth: Use a nitrogen-rich fertilizer to encourage vine development.
• After flowering begins: Switch to a phosphorus and potassium-rich fertilizer to support fruit growth.

Tip: Don’t overdo nitrogen late in the season—it can lead to lots of vine growth but fewer fruits.

Pollination Matters

Watermelon plants have separate male and female flowers. Bees and other pollinators are crucial for moving pollen between them.

• Encourage pollinators by planting flowers nearby.
• Hand pollinate if necessary: take a male flower, peel back the petals, and gently brush the pollen onto the center of a female flower.

You’ll know a female flower by the tiny fruit-shaped bump below the petals.

How to Know When a Watermelon Is Ripe

This is the trickiest part—but there are a few good clues:

• The tendril nearest the fruit turns brown and dries out.
• The underside of the melon (the “belly spot”) changes from white to a creamy yellow.
• The melon sounds hollow when tapped.

Resist the urge to pick too early. Watermelons don’t continue ripening after harvest.

Harvest and Enjoy!

Once ripe, use a sharp knife or pruners to cut the melon from the vine, leaving about an inch of stem. Chill it, slice it, and enjoy your sweet, juicy reward!

Bonus: save the seeds from open-pollinated varieties to plant next year.

Common Watermelon Growing Problems (And Fixes)

• Poor fruit set? Add more pollinators or try hand-pollination.
• Yellow leaves? Could be overwatering, nutrient deficiency, or pests like aphids.
• Cracked fruit? Inconsistent watering can cause splitting—stick to a steady schedule.

Final Tips for Sweet Success

• Rotate your crops each year to avoid soil-borne diseases.
• Don’t plant watermelons near cucumbers or squash, as they share pests.
• Give vines space to roam, or try trellising small varieties with support for the fruits.

Ready to Grow Your Own?

Growing watermelons from seeds may take a little time, sun, and patience—but the taste of your own homegrown melon is so worth it.

Have you tried growing watermelons before? Share your experience—or your biggest challenge—in the comments below. Let’s swap tips and stories!

And if you’re just getting started, don’t forget to bookmark this guide for your garden journey.