When to plant cucumbers in Duluth: 28 June – 13 August

In Duluth, cucumber: sow for seedlings from 10 May to 16 July; plant into a greenhouse from 7 June to 13 August; plant out into open ground from 28 June to 13 August. For plants and seeds, the places nearby include Growing Duluth (garden centre, 7 km); addresses and opening hours are below.

Cucumber in Duluth: soil, season and weather

In Duluth 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 cucumber card — only around 28 June, 61 days later.

Last spring frost	28 April
Top 7 cm of soil at 18 °C	28 June, 61 days after the last frost
Into an unheated greenhouse	7 June – 13 August; June outside: 12.8 °C at night, 21.9 °C by day; card 18–25 °C
First autumn frost	28 October, 122 days after the start
Days in the bed to the first harvest (card)	34
First harvest, if planted in this window	1 August – 16 September
Days left for picking	88
Daylight	15:34 on 31 May, 15:50 on 28 June
Watering outdoors when fruiting (card)	every 2 days; the driest month, October, has 11 rainy days

The same dates in Duluth hold for Bell Pepper, Eggplant, Zucchini, Pumpkin and Watermelon.

Cucumber in Duluth: care after planting

Planted on 28 June: in the first weeks water every 4 days.

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

5 July — feed: nitrogen

Pests and diseases of cucumber 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 Duluth during the cucumber season

No month of the season averages above the cucumber card's 18–35 °C by day; the warmest, July, averages 25.5 °C. Months that stay below 18 °C even by day on average: October (13.1 °C). Nights average below 18 °C in every month of the season, from 7 °C to 17.3 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	21.9	12.8	87	11	15:50
July	25.5	17.3	85	10	15:31
August	24.4	17.2	88	10	14:15
September	21	14	90	10	12:37
October	13.1	7	72	11	10:58

ERA5 2016–2025, Open-Meteo

Cucumber in nearby cities

Around Duluth, Green Bay is 32 days earlier and Thunder Bay 10 days later.

City	Distance	Date	Difference
Minneapolis	219 km	28 May – 9 August	31 days earlier
Thunder Bay	279 km	8 July – 8 August	10 days later
Fargo	356 km	31 May – 1 August	28 days earlier
Grand Forks	396 km	5 June – 1 August	23 days earlier
Green Bay	405 km	27 May – 15 August	32 days earlier
Madison	464 km	28 May – 12 August	31 days earlier

Where to buy cucumber plants and seeds near Duluth

Buy plants ready to set out from 28 June to 13 August (from 7 June to 13 August for an unheated greenhouse); seed for raising your own is sown from 10 May to 16 July. Within 15 km of Duluth OpenStreetMap lists 1 garden centre and 1 market (collected 28 October 2026).

Growing Duluth — garden centre
Cody Street 6616, 55807 Duluth · 7 km · growingduluth.com
Farmer's Market — market
East 3rd Street 1324, 55805 Duluth · May–Oct: Wed 14:00–17:00, Sat 08:00–12:00; public holidays · 3 km · duluthfarmersmarket.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.

Questions