When to plant zucchini in Grand Forks: 5 June – 30 July

In Grand Forks, zucchini: sow for seedlings from 24 April to 9 July; plant into a greenhouse from 15 May to 30 July; plant out into open ground from 5 June to 30 July.

Zucchini in Grand Forks: soil, season and weather

In Grand Forks the soil, not frost, sets the date: the last frost is over around 10 May, but the top 7 cm of soil reaches 18 °C — the minimum on the zucchini card — only around 5 June, 26 days later.

Last spring frost	10 May
Top 7 cm of soil at 18 °C	5 June, 26 days after the last frost
First autumn frost	16 October, 133 days after the start
Days in the bed to the first harvest (card)	36
First harvest, if planted in this window	11 July – 4 September
Days left for picking	97
Daylight	15:09 on 15 May, 15:51 on 5 June
Watering outdoors when fruiting (card)	every 3 days; the driest month, September, has 8 rainy days

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

Zucchini in Grand Forks: care after planting

Planted on 5 June: in the first weeks water every 4 days.

Pests and diseases of zucchini to watch for:

Weather in Grand Forks during the zucchini season

About 342 mm of rain falls in the season; September is the driest month (60 mm) and June the wettest (89 mm).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	26.3	14.8	89	10	16:00
July	27.9	17.1	72	8	15:40
August	26.3	15.9	61	9	14:20
September	22.2	12.3	60	8	12:38
October	12.8	4.2	60	8	10:55

ERA5 2016–2025, Open-Meteo

Zucchini in nearby cities

Around Grand Forks, Pierre is 11 days earlier and Duluth 23 days later.

City	Distance	Date	Difference
Fargo	118 km	31 May – 30 July	5 days earlier
Winnipeg	220 km	1 June – 26 July	4 days earlier
Bismarck	303 km	31 May – 29 July	5 days earlier
Duluth	396 km	28 June – 11 August	23 days later
Minneapolis	439 km	28 May – 7 August	8 days earlier
Pierre	467 km	25 May – 7 August	11 days earlier

Where to buy zucchini plants and seeds near Grand Forks

Buy plants ready to set out from 5 June to 30 July (from 15 May to 30 July for an unheated greenhouse); seed for raising your own is sown from 24 April to 9 July. Within 15 km of Grand Forks OpenStreetMap lists 2 markets (collected 29 October 2026).

Town Square Farmers Market — market
Jun 17–Sept 30 Sat 09:00–13:00 · 5 km · tsfarmersmarket.com
Daryeel Grocerys — market
5 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.

Questions