🍉 Allsweet Watermelon

What it looks like

Why this variety

Allsweet is the watermelon Southern growers plant when they have been burned before: a long, striped melon with sweet red flesh, bred with resistance to anthracnose and fusarium wilt — two diseases that end melon seasons in humid climates. Resistance is not immunity, but it is the difference between a harvest and a story about the harvest you almost had.

The fruit is the classic oblong picnic melon, typically 25–30 pounds, with a rind pattern of dark and light green stripes and flesh that is sweet, crisp, and seedy in the old-fashioned way. Allsweet is an open-pollinated variety, so you can save seed — with the usual cucurbit caveat about crossing with other watermelons nearby.

Florida translation: Allsweet is one of the most sensible watermelon choices for Florida, where humidity drives anthracnose and fusarium pressure all summer. Plant in warm soil, mulch heavily once soil warms, taper water as fruit ripens so sugars concentrate, and pick on the tendril-and-thump test rather than the calendar.

For the species as a whole, see the Watermelon growing guide.

How to grow

Direct-sow after all frost danger, when soil is at least 70°F; watermelon seed sulks in cold soil and rotting seed is the usual cause of a blank hill. Sow 1 inch deep, 3–4 seeds per hill, and thin to the 2 strongest plants. In short-season zones, start indoors 3–4 weeks before last frost in peat pots — watermelon roots resent disturbance — and choose an early variety plus black plastic mulch to bank extra heat. Vines run 6–15 feet, so plan for sprawl or train them up a very sturdy trellis (fruit in slings if you go vertical). Bees do the pollination, and a watermelon flower that is not visited simply drops, so plant flowers nearby and skip row cover once bloom starts. One plant typically carries 2–4 good fruit; pinch off extra fruit late in the season so the plant finishes what it started.

Sow Allsweet directly in warm soil (at least 70°F), 1 inch deep, and thin hills to the 2 strongest plants; give vines room to run 6–15 feet.

Water & feeding

Deep, regular water — 1–2 inches a week — while vines grow and fruit sizes up, then taper off as fruit approaches ripeness: heavy late watering dilutes sugars. Work worm castings into each hill at planting and side-dress at flowering; castings carry a low burn risk and feed steadily without the nitrogen surge that grows vines at the expense of fruit. Mulch heavily once soil is warm to hold moisture and keep fruit clean.

Common problems

• Poor fruit set: usually missing pollinators or cold nights — hand-pollinate morning flowers (male to female; females carry a tiny melon behind the petals) and be patient in cool weather.
• Cucumber beetles: row cover until flowering; they spread bacterial wilt, which has no cure once established.
• Blossom end rot (black, sunken blossom end): uneven watering interrupting calcium movement — mulch and water evenly rather than reaching for a calcium spray.
• Hollow heart or cracked fruit: sudden water after drought, or over-ripe fruit left on the vine — keep moisture even and harvest on time.

Harvest

Thump, look, and check the tendril: a ripe watermelon sounds dull and hollow (not high-pitched), the underside spot where it sat on the ground has turned from white to creamy yellow, and the curly tendril nearest the fruit stem has dried and browned. Cut, do not pull, the stem, and chill promptly. A watermelon picked early will not sweeten off the vine.

Saving seeds

Allsweet is open-pollinated, so you can save seed — with the usual cucurbit caveat about crossing with other watermelons nearby. The full method is in the Saving seeds section of the Watermelon guide.