When to plant zucchini in Duluth: 28 June – 11 August

In Duluth, zucchini: sow for seedlings from 17 May to 21 July; plant into a greenhouse from 7 June to 11 August; plant out into open ground from 28 June to 11 August. For plants and seeds, the places nearby include Growing Duluth (garden centre, 7 km); addresses and opening hours are below.

Zucchini 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 zucchini 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
First autumn frost	28 October, 122 days after the start
Days in the bed to the first harvest (card)	36
First harvest, if planted in this window	3 August – 16 September
Days left for picking	86
Daylight	15:44 on 7 June, 15:50 on 28 June
Watering outdoors when fruiting (card)	every 3 days; the driest month, October, has 11 rainy days

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

Zucchini in Duluth: care after planting

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

Pests and diseases of zucchini to watch for:

Weather in Duluth during the zucchini season

About 422 mm of rain falls in the season; October is the driest month (72 mm) and September the wettest (90 mm).

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

Zucchini 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 – 7 August	31 days earlier
Thunder Bay	279 km	8 July – 6 August	10 days later
Fargo	356 km	31 May – 30 July	28 days earlier
Grand Forks	396 km	5 June – 30 July	23 days earlier
Green Bay	405 km	27 May – 13 August	32 days earlier
Madison	464 km	28 May – 10 August	31 days earlier

Where to buy zucchini plants and seeds near Duluth

Buy plants ready to set out from 28 June to 11 August (from 7 June to 11 August for an unheated greenhouse); seed for raising your own is sown from 17 May to 21 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