How to Grow Watermelon That's Sweet and Juicy This Summer

Use these tips to grow the juiciest, sweetest watermelon possible—all you need is a seed, well-drained soil, water, and sun.

Biting into a juicy slice of fresh watermelon is an essential part of summer. You can hardly have a barbecue or picnic without including a platter because it's just so refreshing on a hot day. But if you've always picked your watermelons from the supermarket, you're seriously missing out on flavor. Growing your own and letting them ripen in the sun is a must for any true watermelon fan; they'll have better flavor, and you can take one straight from your garden to your table. All you need to get started is a sunny spot in your yard and a few seeds.

The first step in growing juicy and delicious watermelons is to choose what type you want to grow. There are three main kinds: Early season, main season, and seedless watermelons. Within those categories, you can choose flesh that's red, pink, yellow, or orange. An early-season watermelon is sometimes called an icebox melon because it grows to a petite size that easily fits on a refrigerator shelf. It takes the shortest amount of time to mature, about 70 to 75 days. A main-season watermelon is larger and takes longer to ripen, usually 80 to 90 days.

Seedless watermelons are an interesting exercise in plant genetics. Plant breeders make several crosses to create seeds for watermelon plants that can't produce seeds themselves but can grow fruit when their blossoms are pollinated from regular seeded watermelons growing nearby. Seedless watermelons grow like other types of watermelons, but since they're not busy putting energy into producing seeds, seedless types are often sweeter and the vines become more vigorous throughout the summer.

watermelon on ground
Blaine Moats

When to Plant Watermelon

In some northern climates, the growing season may not be warm long enough to produce good watermelons from seed. Two to three weeks before your last frost, start watermelon seeds indoors. Plant watermelon seeds in a soilless potting mix.

Keep seedlings warm and moist until outdoor temperatures consistently stay above 50°F or warmer. Don't start watermelon seeds too early, as large plants transplant poorly into the garden; once planted, watermelons don't like their roots disturbed.

You can sow watermelons directly into the ground when the soil temperature is above 65°F. Plant seeds 1/2 to 1 inch deep, placing two or three seeds in groups 18 to 24 inches apart. Once watermelon seedlings are established, remove two and leave the best watermelon plant in each group.

Watermelons need soil that is well-drained and sandy. They also need a pH level between 6.0 and 6.5, a very narrow range. Test your soil before adding any compost or fertilizer to know if you need to add any nutrients and in what amounts, and water your watermelon plants regularly when they're young. Typically, watermelon plants need 1-2 inches of water per week so that the soil stays moist but not wet. If you're not getting enough rain each week, make sure you give your plants an extra drink.

Avoid "weed and feed" types of fertilizers. They contain weed killers that kill fruit and vegetable plants. They also kill annual flower seeds but are fine for use around shrubs and perennial plants.

To suppress weeds and keep soil moist, apply a 1- to 2-inch layer of organic mulch around watermelon vines when they reach 6 to 8 inches long. Frequently hand-pull weeds when they're small; if you wait until weeds are large, the weeds' large root systems could disturb a watermelon's shallow roots.

Once watermelon vines begin producing blossoms, the key to fruit set is pollination by bees. Avoid spraying for flying insects; chemicals can kill the beneficial bugs your plants need.

watermelon on plant
Peter Krumhardt

How to Get Sweet Watermelons

Why are some melons so sweet while others seem to be fibrous and tasteless? To get high sugar content, you'll need to keep watermelon plants happy all season with the right amount of water, protection from diseases and pests, and the addition of extra nutrients to the soil. An especially cool growing season can also affect watermelon quality.

How to Grow Seedless Watermelons

Seedless watermelons may not germinate as well as other watermelons, so start more seeds than you need indoors in peat pots. Once they're transplanted into the garden, follow the same directions as for seeded watermelons. Seedless watermelons need pollen from a seeded type to produce, so you need to plant both kinds near each other.

sliced watermelon on cutting board with knife
Blaine Moats

How to Tell When a Watermelon Is Ripe

How do you know when a watermelon is ripe? It's best not to rely on the time-honored "thump" method, because it simply doesn't work. Instead, take a look at these telltale signs:

  • One of the best clues is to look at the spot where the melon has been resting on the ground. It has probably been pale green or white during the growing season. When it turns yellow, it's a sign of ripeness. Be careful not to rotate your melon too much when you check the coloring or you may damage the vine. Just tip the fruit up enough to peek under it.
  • On ripe melons, the green, curly tendrils near the stem start to dry out and turn brown.
  • The surface color of your melon may appear dull instead of shiny.
  • The skin resists the poke of a fingernail.

Whether you like early season, main season, or seedless watermelons, growing your own watermelon is super simple. Be sure to keep your watermelon plants happy all season with the right amount of water, protection from diseases and pests, and the addition of extra nutrients to the soil.

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