When to plant watermelons in Columbus: 20 May – 24 July

In Columbus, watermelon: sow for seedlings from 1 April to 26 June; plant into a greenhouse from 29 April to 24 July; plant out into open ground from 20 May to 24 July. For plants and seeds, the places nearby include Strader's (garden centre, 5 km); addresses and opening hours are below.

Watermelon in Columbus: soil, season and weather

In Columbus the soil, not frost, sets the date: the last frost is over around 22 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 20 May, 28 days later.

Last spring frost	22 April
Top 7 cm of soil at 18 °C	20 May, 28 days after the last frost
Into an unheated greenhouse	29 April – 24 July; April outside: 5.7 °C at night, 17.1 °C by day; card 18–35 °C
First autumn frost	2 November, 166 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	18 July – 21 September
Days left for picking	107
Daylight	13:32 on 22 April, 14:31 on 20 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, September, has 9 rainy days

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

Watermelon in Columbus: care after planting

Planted on 20 May: in the first weeks water every 5 days.

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

20 May — 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 Columbus during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 29.4 °C. Months that stay below 18 °C even by day on average: November (11.2 °C). Nights average below 18 °C in May, June and September–November (2.1–16.8 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	22.6	12	126	16	14:22
June	27.4	16.8	119	13	14:59
July	29.4	19.5	128	14	14:45
August	28.3	18.3	100	12	13:47
September	26	15.5	78	9	12:30
October	19.3	9.3	86	9	11:12
November	11.2	2.1	79	9	10:00

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Columbus, Cincinnati is 7 days earlier and Cleveland 8 days later.

City	Distance	Date	Difference
Dayton	104 km	16 May – 31 July	4 days earlier
Cincinnati	159 km	13 May – 31 July	7 days earlier
Toledo (United States)	193 km	24 May – 29 July	4 days later
Cleveland	203 km	28 May – 12 August	8 days later
Charleston, West Virginia	214 km	15 May – 29 July	5 days earlier
Fort Wayne	220 km	21 May – 24 July	1 day later

Where to buy watermelon plants and seeds near Columbus

Buy plants ready to set out from 20 May to 24 July (from 29 April to 24 July for an unheated greenhouse); seed for raising your own is sown from 1 April to 26 June. Within 15 km of Columbus OpenStreetMap lists 9 garden centres, 1 farm-supply shop, 9 markets and 2 farm shops (collected 20 October 2026).

Strader's — garden centre
King Avenue 1354 · 5 km
North Market — market
Spruce Street 59, 43215 Columbus · Sun, Mon 10:00–17:00; Tue–Sat 09:00–19:00 · 1 km · northmarket.com
The Little Grand Market — market
Grandview Crossing Way 710, 43215 Columbus · Sun–Thu 11:00–22:00; Fri–Sat 11:00–23:00 · 4 km · thelittlegrandmarket.com
The Pearl Market — market
May–Oct: Tue, Fri 10:30–14:00 · 0 km · pearlmarket.org

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.

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