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Watermelon

Citrullus lanatus · Cucurbitaceae

Summer classic; icebox types fit home gardens

Sun: Full sun
Soil: Sandy, well-drained, warm soil
Soil pH: Prefers about 6.0-7.0; tolerates up to 8.0
Water: Regular, even moisture (possibly several times a week on sandy soil). Avoid overwatering and overhead watering
Hardiness: Frost-tender warm-season annual. Plant only after frost, when the soil reaches 65-70°F
Height and spread: Sprawling vines, typically 5-10 ft long. Mounds about 4 ft apart, rows 4-6 ft apart

Guv's tipWatermelons like sandy, warm, well-drained soil and regular, even moisture. Just don't overwater or water overhead. Simple as that.

Through the year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Sow or plant

Harvest

Months are a rough guide. Time it by your own frost dates: after last frost (warm season).

When to plant

After the last frost, in warm soil: Apr-Jun in the South (South Carolina Apr 1-Jun 15), May-Jun further north

Harvest or flowering

Harvest 70-90 days from planting, about Jul-Sep

Pruning

None

Making more plants

Seed

Watch out for

Pest

Cucumber beetles

Look for: Striped/spotted beetles feeding on seedlings and vines; transmit bacterial wilt

What to do: Row covers on young plants; labeled insecticide at first appearance

Pest

Aphids

Look for: Clusters under leaves, crinkled/curled leaves, sticky honeydew; spread viruses

What to do: Strong water spray, insecticidal soap

Disease

Anthracnose

Colletotrichum orbiculare

Look for: Dark leaf lesions, sunken fruit spots

What to do: Rotation 3+ years, avoid overhead watering, labeled fungicide

Disease

Fusarium wilt

Fusarium oxysporum f. sp. niveum

Look for: Wilting of one or more vines, plant death

What to do: Resistant cultivars, long rotation

Always read and follow the label on any treatment, and check it is approved for use where you live.

Safety and spread

Pets and people: Not listed on the ASPCA toxic plant list. The fruit flesh is safe for dogs without the seeds and rind

Weed risk: Not on the federal noxious weed list, and no noxious status in the USDA PLANTS database

Checked against two or more reputable gardening sources. How we check our facts

Keep it by the back door

The Plant Doctor and the Guv's book

Printable pest and disease charts with real photographs, and all 50 USA plants in one book.

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