When to plant watermelons in Louisville: 7 May – 2 August

In Louisville, watermelon: sow for seedlings from 19 March to 5 July; plant into a greenhouse from 16 April to 2 August; plant out into open ground from 7 May to 2 August.

Watermelon in Louisville: soil, season and weather

In Louisville the soil, not frost, sets the date: the last frost is over around 6 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 7 May, 31 days later.

Last spring frost	6 April
Top 7 cm of soil at 18 °C	7 May, 31 days after the last frost
Into an unheated greenhouse	16 April – 2 August; April outside: 8.2 °C at night, 19.6 °C by day; card 18–35 °C
First autumn frost	11 November, 188 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	5 July – 30 September
Days left for picking	129
Daylight	12:56 on 9 April, 13:59 on 7 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 8 rainy days

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

Watermelon in Louisville: care after planting

Planted on 7 May: in the first weeks water every 5 days.

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

7 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 Louisville 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: November (13.6 °C). Nights average below 18 °C in May and September–November (4.1–17.2 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	24.5	14.1	118	14	14:14
June	29.3	18.7	106	11	14:49
July	31	21.3	129	14	14:35
August	29.8	20.1	86	11	13:41
September	27.6	17.2	91	7	12:28
October	21.3	11.3	95	9	11:15
November	13.6	4.1	85	8	10:07

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Louisville, Bowling Green is 3 days earlier and Indianapolis 9 days later.

City	Distance	Date	Difference
Frankfort	78 km	13 May – 25 July	6 days later
Lexington	116 km	15 May – 29 July	8 days later
Cincinnati	146 km	13 May – 31 July	6 days later
Bowling Green	153 km	4 May – 1 August	3 days earlier
Evansville	159 km	5 May – 1 August	2 days earlier
Indianapolis	173 km	16 May – 28 July	9 days later

Where to buy watermelon plants and seeds near Louisville

Buy plants ready to set out from 7 May to 2 August (from 16 April to 2 August for an unheated greenhouse); seed for raising your own is sown from 19 March to 5 July. Within 15 km of Louisville OpenStreetMap lists 1 garden centre, 1 farm-supply shop, 1 plant nursery and 7 markets (collected 20 October 2026).

The District - Artisan Market & Patio — market
East 15th Street 845, 47150 New Albany · 7 km
All Peddlers — market
Preston Highway 7100, 40219 Louisville · 13 km
Wallitsch Nursery — plant nursery
11 km
Rual king — farm supply
9 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