Watermelon seeds germinate optimally in warm soil temperatures, with the ideal range falling between 70°F (21°C) and 95°F (35°C). However, the optimal temperature for germination is typically around 80°F to 90°F (27°C to 32°C).

Direct sow only if you live in a warm climate.  Otherwise start seeds indoors 4-6 weeks prior to your last frost date.

Watermelon seedlings should be transplanted outdoors after the last expected frost date, typically when the weather has warmed and soil temperatures consistently reach at least 70°F (21°C) or warmer.

Full sunlight: at least 6-8 hours a day.

Space plants 4-6′ apart. Be sure to check the seed packet for specifics on your variety’s size. Watermelon plants can sprawl over 8+ square feet, depending on the variety.

Watermelon love the heat, with optimal daytime temperatures ranging between 75°F and 95°F (24°C to 35°C). While they can tolerate cooler nighttime temperatures, watermelon perform best when nighttime temperatures remain above at least 60°F (15°C). Watermelon are not hardy and will be killed by frost.

Keep the soil consistently moist.  Water at the base of the plants to keep the foliage dry and reduce the risk of diseases.

Watermelons generally do not require pruning for healthy growth or fruit production. If your watermelon plants are dense, prune excess foliage to encourage more fruit production and allow airflow to prevent disease.

A ripe watermelon typically develops a creamy yellow or pale yellow spot, indicating it’s ready for harvest. If the tendril closest to the fruit is brown and withered, it’s a good indication that the watermelon is ready for harvest. Some gardeners swear by the thump: when tapped gently, a ripe watermelon produces a deep, hollow sound. Use a sharp knife or pruners to cut the stem, leaving a few inches attached to the fruit.

Watermelon are typically grown from seeds. If saving seeds from an heirloom variety, be sure to avoid cross-pollination. Different varieties of watermelon will cross-pollinate with each other. 

Watermelons are monoecious plants, meaning they have separate male and female flowers on the same plant. It’s common for the male flowers to appear before the female flowers. After the male flowers have appeared and begun releasing pollen, the plant starts producing female flowers. Female flowers contain the structures that, when pollinated, develop into fruits, so do not fret if your watermelons aren’t producing any fruit with the appearance of the first flowers.  This is completely normal, and you will have fruit before long.