Charleston Gray Watermelon
Citrullus lanatus 'Charleston Gray'
fruitCharleston Gray is the legendary 1954 USDA-bred heirloom watermelon (developed by Charles Andrus at the USDA vegetable lab in Charleston, South Carolina), producing huge 22 to 26 inch oblong fruits (25 to 35 lb each) with gray-green rind and bright sweet pink-red flesh that stays crisp even in hot weather. The variety carries resistance to fusarium wilt and anthracnose, classic flavor, and excellent storage.
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Sun
full sun
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Water
Every 3 days
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Harvest
~90 days
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Difficulty
easy
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Lifecycle
annual
One season, then done
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Spacing
6 ft between hills, 8-10 ft between rows
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Planting Depth
1 in
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Soil pH
6.0-7.0
Growing Details
Soil Type
Rich, well-draining
Hardiness Zones
Zones 3 – 11
Grown as an annual. This range is its winter hardiness, but you can grow it for a single season in any zone.
When to Fertilize
Pre-plant; side-dress before vines run, again at bloom
Fertilizer
10-10-10 at planting; side-dress with nitrogen (calcium nitrate at 2 lb per 100 ft of row)
🌱 Growing Guide
Direct-sow after the soil reaches 70F and all frost danger has passed (or start indoors 3 weeks ahead). Plant 1 in deep, 3 to 4 seeds per hill with hills 6 ft apart in rows 8 to 10 ft apart. Watermelons need a long warm season; Charleston Gray takes 85 to 95 days. Black plastic mulch warms cool-zone soils. Water deeply at the base while fruit is sizing; cut back as harvest nears to concentrate sugars.
Planting Calendar
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Start seeds indoors
Mar 25
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Transplant outdoors
Apr 29
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Projected first harvest
Jul 28
JJan
FFeb
MMar
AApr
MMay
JJun
JJul
AAug
SSep
OOct
NNov
DDec
✅ Plant alongside
Good neighbors that attract beneficial insects or deter pests
- Nasturtiums: Trap crop for squash bugs and aphids
- Marigolds: Suppress nematodes in the cucurbit root zone
- Borage: Bee magnet that boosts pollination
- Radish: Trap crop for cucumber beetles at the corners
❌ Keep away from
Potato
🛡️ Pest & disease prevention
Proactive ways to stop trouble before it starts. Tap a name with an arrow for its full guide
Row cover until female flowers open; the beetles also vector bacterial wilt
Wrap stems with foil collars near the soil; cut out borers if frass appears
Charleston Gray is resistant by breeding; rotate cucurbits for 3 years
Water at the base, prune for airflow, and use weekly milk sprays late in the season
🌾 Harvest & storage
Charleston Gray is ready when the underside ground spot turns creamy yellow, the tendril nearest the fruit dries up, and the surface dulls from glossy to matte. The classic thump test: a ripe melon sounds hollow rather than tight. Cut the stem with pruners; do not pull (which damages the vine). Refrigerated, a whole melon keeps 1 to 2 weeks; cut watermelon needs to be eaten within 3 days.
🥗 Nutrition & benefits
About 30 calories per 100 g with 0.4 g fiber, 8.1 mg vitamin C, and 112 mg potassium. Watermelon is 92 percent water and supplies high levels of lycopene (the same red pigment in tomatoes), an antioxidant linked to cardiovascular and prostate health.
For educational and informational purposes only. HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.