Garden Blog

How to Grow Watermelons

How to Grow Watermelons

Did you know that watermelon has more lycopene than any other fresh fruit or vegetable? Lycopene is an antioxidant linked to decreased risk of cancer, heart disease, and age-related eye disorders. It’s also high in vitamin A and is one of the crops that if grown yourself, will change the way you look at a store-bought melon forever. Sweet, delicious, and nutritious, homegrown watermelon might just be the perfect summertime snack. While it’s true that they can take up a lot of space, making it difficult for backyard gardeners to justify giving it the room, the benefits can be worth it, not to mention that the fun of a good seed spitting competition is a dying art form.

Baby Watermelon on the Plant

Crop Description:

There are two basic types of watermelons: vining and bush. Both types thrive in long, hot summers and bear round or oval fruit. Modern hybrids and newly bred open-pollinated varieties are coming into availability in compact, 7–12-pound fruit sizing meant for small gardeners and to fit into refrigerators easily. Small fruits can be an advantage because they often take less time to ripen, though this is occasionally at the expense of flavor. Newer bush-types are also available to grow now and are perfect for smaller gardens and even for growing in containers. Their designation is a little misleading, as they aren’t actually bushes like a summer squash for example, rather just much shorter vines.

Planting and Aftercare:

Prep your soil by mixing in an abundance of compost with a shovel to a depth of at least 12” in a row about 8-12” wide. Melons of all kinds are commonly planted on the top of soil mounds made up of your existing garden soil or with a couple shovels of compost on top of your prepared garden space. Form your mounds about 6 feet apart. Cooler growing zones may find it helpful to pre-warm the soil with black plastic or dark mulch. When your weather is consistently above 60° F at night and day temps of 80°+ you can go ahead and plant your seeds 4-8 seeds per mound. As your seedlings grow two sets of true leaves, thin to the two strongest looking plants per mound. As your plants grow, it’s very important to keep the plants well-watered, being careful to try and not water the foliage which can contribute to the spread of disease. As fruits form, place several inches of straw under each developing watermelon. This will keep the fruit off of the ground, preventing rotting. Feed with your favorite, water-soluble, all-purpose fertilizer every 2-4 weeks. Harvest melons when their curly tendrils are brown and shriveled and/or the fruits sound hollow when tapped.

Watermelons Growing in the Garden

Tips for Success:

Watermelons will do best direct seeded, but if you need to extend your season by starting seeds indoors, or are just tempted at your local nursery, buy small plants with deep green, healthy looking leaves. Plants in 4-6” pots will suffer from less chance of transplant shock. Avoid plants that are already flowering, are leggy, or have visible roots extending through their drainage holes.
If starting indoors, aim to have your plants no more than 4-6 weeks old when you transplant them outside.

Pests to Watch For:

Fusarium wilt is a disease carried by the striped cucumber beetle. It causes vines to wilt and stop growing. Remove and destroy (not in your compost pile) affected plants, cover young plants with a floating row cover to keep beetles away. Remove your cover when the vine starts to flower so pollinators can access the flowers or your plant will not grow fruit.
Very small melons, few fruits on the vine, or black, rotten looking ends on your fruits (called blossom end rot) are all usually the result of insufficient amounts of water or nutrients during the fruits’ formation. Keep plants well-watered and fertilized. Hard soil can also cause small melons by restricting root growth. It is important to work in a copious amount of organic matter in subpar soils for growing melons.

Harvested Watermelon Cut Open

Growing Zone and Special Conditions:

Watermelons are annuals and will grow in most areas of the United States. They are not a crop for faint of heart, because when something goes wrong it can take a trained eye to spot it and can often lead to total plant failure. This can be heartbreaking because of the amount of room the plants take up that could have been used for something else. Practice makes perfect with this crop though, and one bite of sun-warmed sweetness will make you a believer.
It should be mentioned that small fruiting varieties can be grown and trained up a trellis to save some space. They aren’t natural climbers though, so you’ll have to manage the vines and attach them to the (very sturdy) trellis yourself, and you’ll also need to buy or fashion fruit slings that will hold the fruits to the trellis and keep them from pulling off of the vines before they are ripe.

Shop Watermelon seeds here:

What have your watermelon growing experiences been like? Share your successful tips or problems we might be able to help with in the comments so we can all learn together!  <3

 Written by Sow True Seed's Education Director, Angie Lavezzo.