When to plant watermelons in Grand Rapids: 28 May – 25 July

In Grand Rapids, watermelon: sow for seedlings from 9 April to 27 June; plant into a greenhouse from 7 May to 25 July; plant out into open ground from 28 May to 25 July. For plants and seeds, the places nearby include Flowerland (garden centre, 5 km) and Flowerland (garden centre, 8 km); addresses and opening hours are below.

Watermelon in Grand Rapids: soil, season and weather

In Grand Rapids the soil, not frost, sets the date: the last frost is over around 28 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 28 May, 30 days later.

Last spring frost	28 April
Top 7 cm of soil at 18 °C	28 May, 30 days after the last frost
Into an unheated greenhouse	7 May – 25 July; May outside: 9.4 °C at night, 20.8 °C by day; card 18–35 °C
First autumn frost	3 November, 159 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	26 July – 22 September
Days left for picking	100
Daylight	14:03 on 30 April, 15:02 on 28 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 10 rainy days

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

Watermelon in Grand Rapids: care after planting

Planted on 28 May: in the first weeks water every 5 days.

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

28 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 Grand Rapids during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 28.2 °C. Months that stay below 18 °C even by day on average: October (16.3 °C) and November (8.2 °C). Nights average below 18 °C in every month of the season, from 1.3 °C to 17.9 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	20.8	9.4	100	12	14:38
June	26.5	15.4	104	11	15:20
July	28.2	17.9	81	11	15:04
August	27.3	17.1	98	10	13:58
September	23.9	14.2	69	9	12:33
October	16.3	8	109	13	11:06
November	8.2	1.3	64	10	9:45

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Grand Rapids, Fort Wayne is 7 days earlier and Traverse City 8 days later.

City	Distance	Date	Difference
Lansing	95 km	28 May – 24 July	same day
Ann Arbor	174 km	29 May – 27 July	1 day later
Milwaukee	182 km	28 May – 23 July	same day
Chicago	201 km	28 May – 28 July	same day
Traverse City	201 km	5 June – 31 July	8 days later
Fort Wayne	214 km	21 May – 24 July	7 days earlier

Where to buy watermelon plants and seeds near Grand Rapids

Buy plants ready to set out from 28 May to 25 July (from 7 May to 25 July for an unheated greenhouse); seed for raising your own is sown from 9 April to 27 June. Within 15 km of Grand Rapids OpenStreetMap lists 7 garden centres, 2 plant nurseries, 7 markets and 9 farm shops (collected 20 October 2026).

Rakowski Family Farm Market — farm shop
2 km
Flowerland — garden centre
28th Street Southwest 765, Wyoming · Mon–Sat 10:00–18:00 · 5 km · myflowerland.com
S&H Greenhouses — garden centre
Cannonsburg Road Northeast 4525, 49306 Belmont · Mon–Fri 09:00–19:00; Sat 09:00–17:00; Sun 11:00–15:00 · 14 km · shgreenhouses.net
Flowerland — garden centre
Alpine Avenue Northwest 3801, Comstock Park · 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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