When to plant watermelons in Charleston: 12 March – 10 September

In Charleston, watermelon: sow for seedlings from 22 January to 13 August; plant into a greenhouse from 19 February to 10 September; plant out into open ground from 12 March to 10 September. For plants and seeds, the places nearby include Fresh Future Farm (Urban Farm) (farm shop, 9 km); addresses and opening hours are below.

Watermelon in Charleston: soil, season and weather

In Charleston the soil, not frost, sets the date: the last frost is over around 4 February, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 12 March, 36 days later.

Last spring frost	4 February
Top 7 cm of soil at 18 °C	12 March, 36 days after the last frost
Into an unheated greenhouse	19 February – 10 September; February outside: 9.4 °C at night, 17.8 °C by day; card 18–35 °C
First autumn frost	20 December, 283 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	10 May – 8 November
Days left for picking	224
Daylight	10:55 on 12 February, 11:50 on 12 March
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 8 rainy days

The same dates in Charleston hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.

Watermelon in Charleston: care after planting

Planted on 12 March: in the first weeks water every 5 days.

Feeding, by the card’s schedule from that day:

12 March — feed: balanced (NPK)

Pests and diseases of watermelon to watch for:

Dates count from the first planting day of the window above; a later planting moves them by as many days.

Weather in Charleston during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 31 °C. Months that stay below 18 °C even by day on average: December (16.5 °C). Nights average below 18 °C in March, April and October–December (8.4–17 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
March	20.1	11.6	80	8	11:56
April	23.4	15	99	7	12:58
May	27	19.4	107	12	13:50
June	29.5	22.8	146	16	14:18
July	31	24.7	153	20	14:07
August	29.9	24.1	201	20	13:23
September	28.3	21.7	155	13	12:24
October	24.7	17	87	7	11:24
November	19.9	11.4	76	8	10:29
December	16.5	8.4	121	9	10:00

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Charleston, Jacksonville is 29 days earlier and Greenville 42 days later.

City	Distance	Date	Difference
Savannah	135 km	25 February – 14 September	15 days earlier
Columbia	170 km	28 March – 20 August	16 days later
Wilmington	247 km	2 April – 22 August	21 days later
Charlotte	285 km	13 April – 4 August	32 days later
Jacksonville	318 km	11 February – 17 September	29 days earlier
Greenville	326 km	23 April – 13 August	42 days later

Where to buy watermelon plants and seeds near Charleston

Buy plants ready to set out from 12 March to 10 September (from 19 February to 10 September for an unheated greenhouse); seed for raising your own is sown from 22 January to 13 August. Within 15 km of Charleston OpenStreetMap lists 7 garden centres, 5 markets and 3 farm shops (collected 20 October 2026).

Fresh Future Farm (Urban Farm) — farm shop
Success Street 2008, 29405 North Charleston · 9 km · freshfuturefarm.org
Meeting Green — garden centre
5 km
Royal Ace Hardware — garden centre
7 km
Walmart Garden Center — garden centre
7 km

Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

Questions