When to plant watermelons in Spokane: 22 May – 6 July

In Spokane, watermelon: sow for seedlings from 3 April to 8 June; plant into a greenhouse from 1 May to 6 July; plant out into open ground from 22 May to 6 July. For plants and seeds, the places nearby include Fern Plant Shop (garden centre, 1 km) and Northwest Seed and Pet (garden centre, 4 km); addresses and opening hours are below.

Watermelon in Spokane: soil, season and weather

In Spokane the soil, not frost, sets the date: the last frost is over around 21 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 22 May, 31 days later.

Last spring frost	21 April
Top 7 cm of soil at 18 °C	22 May, 31 days after the last frost
Into an unheated greenhouse	1 May – 6 July; May outside: 7.8 °C at night, 21.2 °C by day; card 18–35 °C
First autumn frost	15 October, 146 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	20 July – 3 September
Days left for picking	87
Daylight	14:06 on 24 April, 15:24 on 22 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, July, has 2 rainy days

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

Watermelon in Spokane: care after planting

Planted on 22 May: in the first weeks water every 5 days.

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

22 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 Spokane during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 31.3 °C. Months that stay below 18 °C even by day on average: October (15.3 °C). Nights average below 18 °C in every month of the season, from 3.8 °C to 15.9 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	21.2	7.8	50	9	15:07
June	25.5	11.7	30	6	15:58
July	31.3	15.9	6	2	15:38
August	30.9	15.5	14	3	14:19
September	24.8	10.8	20	4	12:38
October	15.3	3.8	56	9	10:55

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

All the nearest cities on our list plant watermelon later than Spokane; the closest date is in Kelowna, 11 days later.

City	Distance	Date	Difference
Missoula	271 km	30 June – 8 August	39 days later
Kelowna	289 km	2 June – 22 July	11 days later
Seattle	367 km	21 June – 15 August	30 days later
Olympia	418 km	26 June – 6 August	35 days later
Helena	425 km	3 July – 5 August	42 days later
Calgary	449 km	18 June – 22 June	27 days later

Where to buy watermelon plants and seeds near Spokane

Buy plants ready to set out from 22 May to 6 July (from 1 May to 6 July for an unheated greenhouse); seed for raising your own is sown from 3 April to 8 June. Within 15 km of Spokane OpenStreetMap lists 13 garden centres, 6 farm-supply shops, 4 plant nurseries and 1 market (collected 20 October 2026).

Northwest Seed and Pet — garden centre
East Sprague Avenue 2422, 99202 Spokane · Mon–Sat 08:00–19:00; Sun 09:00–18:00 · 4 km · nwseed.com
Fern Plant Shop — garden centre
West Riverside Avenue 1526, 99201 Spokane · Mon–Sun 10:00–18:00 · 1 km · fernplantshop.com
Northwest Seed & Pet — garden centre
North Division Street 7302, 99208 Spokane · Mon–Sun 09:00–18:00 · 7 km · nwseed.com
SiteOne Hardscape Center — garden centre
N Fairview Rd 8721, spokane · 10 km · siteone.com

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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