When to plant watermelons in Springfield: 15 May – 23 July

In Springfield, watermelon: sow for seedlings from 27 March to 25 June; plant into a greenhouse from 24 April to 23 July; plant out into open ground from 15 May to 23 July. For plants and seeds, the places nearby include Kreations (garden centre, 7 km) and Brandt (farm supply, 12 km); addresses and opening hours are below.

Watermelon in Springfield: soil, season and weather

In Springfield the soil, not frost, sets the date: the last frost is over around 17 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 15 May, 28 days later.

Last spring frost	17 April
Top 7 cm of soil at 18 °C	15 May, 28 days after the last frost
Into an unheated greenhouse	24 April – 23 July; April outside: 6.8 °C at night, 18 °C by day; card 18–35 °C
First autumn frost	1 November, 170 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	13 July – 20 September
Days left for picking	111
Daylight	13:19 on 17 April, 14:21 on 15 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, September, has 7 rainy days

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

Watermelon in Springfield: care after planting

Planted on 15 May: in the first weeks water every 5 days.

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

15 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 Springfield during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 29.8 °C. Months that stay below 18 °C even by day on average: November (11.6 °C). Nights average below 18 °C in May and September–November (2.6–16.5 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	23.8	13.2	115	12	14:21
June	29.3	18.7	87	11	14:58
July	29.8	20.5	119	12	14:44
August	28.5	19.3	82	10	13:46
September	26.6	16.5	62	7	12:30
October	19.7	9.9	82	10	11:12
November	11.6	2.6	71	8	10:01

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Springfield, Evansville is 10 days earlier and Rockford 13 days later.

City	Distance	Date	Difference
Peoria	99 km	18 May – 22 July	3 days later
St. Louis	139 km	8 May – 26 July	7 days earlier
Davenport	212 km	17 May – 21 July	2 days later
Jefferson City	258 km	11 May – 26 July	4 days earlier
Evansville	271 km	5 May – 1 August	10 days earlier
Rockford	278 km	28 May – 19 July	13 days later

Where to buy watermelon plants and seeds near Springfield

Buy plants ready to set out from 15 May to 23 July (from 24 April to 23 July for an unheated greenhouse); seed for raising your own is sown from 27 March to 25 June. Within 15 km of Springfield OpenStreetMap lists 1 garden centre, 2 farm-supply shops and 1 market (collected 28 October 2026).

Kreations — garden centre
Chatham Road 3427, 62704 Springfield · Tue–Fri 11:00–18:00; Sat 11:00–17:00; Sun 11:00–15:00 · 7 km · gokigc.com
Brandt — farm supply
Industrial Drive 6089, 62670 Curran · 12 km · brandt.co
WinField United — farm supply
Industrial Drive 6100, 62670 Curran · 13 km · winfieldunited.com
Deo Gratias Food Market — market
West Constitution Drive 2920, 62704 Springfield · Tue–Fri 10:00–19:00; Sat 10:30–20:30; Sun 13:00–19:00 · 8 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.

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