Growing Watermelons: How to Plant and Grow Watermelons at Home | The Old Farmer's Almanac

How to Grow Watermelon Plants: The Complete Guide

Photo Credit
Botanical Name
Citrullus lanatus
Plant Type
Sun Exposure
Bloom Time
Flower Color

Sign up for our daily newsletter to get gardening tips and advice.

No content available.

Planting, Growing, and Harvesting Watermelons

Print Friendly and PDF

You can grow watermelons! Watermelons thrive in those hot summer temperatures. This popular melon is easy to grow and ready to harvest in late summer. Plus, the home-grown watermelon is far more flavorful than what you find in any grocery store. Learn how to plant, grow, harvest, and store watermelons.

All About Watermelons

Because watermelons need a long period of warm weather to grow well, they tend to be more popular in warmer climates with long growing seasons. However, gardeners in colder climates can still have success in growing watermelons by starting seeds indoors or purchasing young plants from a nursery, and by growing shorter-season varieties. Depending on the variety of watermelon, it can take between 70 and 100 days to go from planting to harvest.


When to Plant Watermelons

  • In cool climates with short growing seasons, start seeds indoors 2 to 3 weeks before your last frost date. Plan to transplant seedlings into the garden about 2 weeks after that date or when the soil has warmed to at least 65°F (18°C).
  • In warmer climates with long growing seasons, sow seeds directly outdoors 1 to 2 weeks after your last frost date, as long as the soil temperature has warmed to at least 65°F (18°C).
  • Young watermelon plants can also be bought from nurseries. Plant these after there is no longer a chance of frost occurring; they are very tender. Watch the local forecast and err on the side of caution! Consider laying black plastic over your planting area in order to warm the soil even more. 
    • Tip: Starting with young plants can result in an earlier harvest (usually up to 2 weeks earlier), so consider buying young plants, particularly if you live in a cooler climate.

Choosing and Preparing a Planting Site

  • Amend soil with aged manure, seaweed, and/or compost before planting. Watermelons are heavy feeders, meaning they need soil that is fertile and has a high nutrient level. Learn more about soil amendments and preparing soil for planting.
  • Watermelons do best in loamy, somewhat sandy, well-drained soil. They can struggle in soil that contains too much clay and doesn’t drain well.
  • Watermelons prefer a soil pH between 6.0 and 7.5 (“slightly acidic to neutral”).
  • Watermelons need A LOT of space—up to 20 square feet per plant. Their vines need room to sprawl, so plant them in a place where they won’t crowd out other crops.
  • Growing the vines in raised rows, known as hills, ensures good drainage and will hold the sun’s heat longer.
    • Plan to space the plants 2-3 feet apart in a 5-foot-wide hill. 
    • If you’re growing in traditional rows, space them at least 6 feet apart. 

Watermelon plants growing with a watermelon

How to Plant Watermelons

  • Sow seeds 1/2 to 1 inch deep outdoors or 1/4 to 1/2 inch deep in seed-starting pots indoors.
    • Tip: To allow for more root growth, use larger starting pots than you would for most seeds. Also, consider using compostable pots that can be cut away or planted directly in the garden, as this will minimize the risk of damaging seedlings’ tender roots during transplanting.
  • If direct seeding outdoors, sow 4 to 6 seeds per hill, eventually thinning to 2 to 3 seedlings. 

Transplanting Seedlings

  • Handle watermelon seedlings with extreme care when you transplant. Their roots are very fragile, so try not to disturb the soil when removing them from pots.
  • After transplanting, cover the plants with row covers to keep pests at bay. Remember to remove the row covers when you see both male and female flowers on the vine, as pollinators will need to access the flowers.
  • Find even more tips for planting melons in your home garden.

How to Grow Watermelons


  • Watering is very important—from planting until fruit begins to form. While melon plants are growing, blooming, and setting fruit, they need 1 to 2 inches of water per week.
  • Keep soil moist, but not waterlogged. Water at the vine’s base in the morning, and try to avoid wetting the leaves and avoid overhead watering. Reduce watering once fruit are growing. Dry weather produces the sweetest melon.


  • If you choose to fertilize (and many do), make sure it delivers more nitrogen than phosphorus and potassium, as this will encourage leaf and vine growth. However, after flowering begins, use a fertilizer with less nitrogen to instead encourage flowers and fruit. We like to use a seaweed-based fertilizer.

Flowering and Fruiting

  • Vines produce male and female flowers separately on the same plant. They often begin producing male flowers several weeks before the females appear. Do not be concerned if the male flowers fall off. The female flowers (which have a swollen bulb at the base) will stay on the vine and bear fruit.
  • Blossoms require pollination to set fruit, so be kind to the bees! Learn how to support pollinators in your garden.
  • As the fruit is ripening, prevent rotting by gently lifting it and putting cardboard or straw between the fruit and the soil.

Baby watermelon

General Care Tips

  • Mulching with black plastic or straw around the plants will serve multiple purposes: it will warm the soil, hinder weed growth, and keep developing fruits off the soil.
  • Pruning generally isn’t necessary for watermelon plants, but vine productivity may be improved if you do not allow lateral (side) vines to grow and stick to the main vine. When the plant is young, just cut off the end buds as they form (before the side shoots become vines). You can also pinch off some blossoms to focus the energy on fewer melons (though it’s challenging to kill off a potential fruit).

Watermelons don’t continue ripening after they are picked, so harvest time is important. They generally ripen over a two-week period, so keep your eye on them.

How to Tell If a Watermelon Is Ripe

Dr. Bill Rhodes, professor of horticulture at Clemson University, offers the following advice on how to tell when watermelons are ripe:

  • Thump it. If the watermelon sounds hollow, it’s ripe.
  • Look at the color on the top. The watermelon is ripe when there is little contrast between the stripes.
  • Look at the color on the bottom. An immature watermelon will have a white bottom; a ripe melon will have a cream- or yellow-colored bottom.
  • Press on it. If the watermelon sounds like it gives a little, it’s ripe. (Note: Rhodes doesn’t like this method because it can ruin the quality of the fruit.)
  • Check the tendril. If it’s green, wait. If it’s half-dead, the watermelon is nearly ripe or ripe. If the tendril is fully dead, it’s ripe or overripe; it’s not going to get any riper, so you might as well pick!
  • Stems should be cut with a sharp knife close to the fruit.

Check out these tips for more ways to tell if a watermelon is ripe.

How to Store Watermelons

  • Watermelons can be stored uncut for about 10 days. If cut, they can last in the refrigerator for about 4 days. Wrap tightly in plastic.
Gardening Products
Wit and Wisdom
  • What’s in a name? Watermelons are 90% water.
  • The pumpkin vine never bears watermelons.
  • August 3 is National Watermelon Day (U.S.)!
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann

2023 Gardening Club