Botanical name: Citrullus lanatus
Plant type: Fruit
Sun exposure: Full Sun
Soil type: Sandy
Everyone seems to love juicy watermelon in the summertime. Native to Africa, melons need warm temperatures (up to 80 degrees during the day) and a long growing season. Gardeners in colder climates can still have success in growing watermelon by starting seeds indoors and choosing short-season varieties. Days to maturity range from 70 to 90, depending on the variety.
- Amend soil with aged manure or compost before planting.
- Growing the vines in raised rows, known as hills, ensures good drainage and will hold the sun’s heat longer.
- If you are in a cooler zone, start seeds indoors about a month before transplanting. Watermelon vines are very tender and should not be transplanted until all danger of frost has passed.
- If you live in warmer climes, you can direct sow seeds outdoors, but wait until the soil temperature warms to at least 65 degrees to avoid poor germination.
- Space the plants about 2 feet apart in a 5-foot-wide hill.
- Watermelons like loamy, well-drained soil. Handle them gently when you transplant. Add lots of compost to the area before planting and after planting.
- Mulching with black plastic will serve multiple purposes: it will warm the soil, hinder weed growth and keep developing fruits clean.
- Row covers are a good idea to keep pests at bay.
- While melon plants are growing, blooming, and setting fruit, they need 1 to 2 inches of water per week. Water in the morning, and try to avoid wetting the leaves. Reduce watering once fruit are growing. Dry weather produces the sweetest melon.
- Pruning isn't necessary, 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 a challenge to kill off a potential fruit!).
- Vines produce male and female flowers separately on the same plant. They often begin producing male flowers several weeks before the females appear.
- Blossoms require pollination to set fruit, so be kind to the bees!
Watermelons don’t sweeten after they are picked, so harvest time is important. Dr. Bill Rhodes, professor of horticulture at Clemson University, offers the following advice on how to tell if 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. A green 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. (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.
- 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.
- ‘Sugar Baby’ 80 days to maturity. Produces 10-pound melons with bright red flesh.
- ‘Sweet Beauty’ 80 days to maturity. A 2004 All-America Selection. Bears 6-pound, oblong melons with red flesh.
- ‘Golden Midget’ 70 days to maturity. Bears petite, yellow-skinned 3-pound melons with pink flesh. Good for Northern gardeners.
Wit & Wisdom
What’s in a name? Watermelon is 90% water.
The pumpkin vine never bears watermelons.