When to plant eggplants in Thunder Bay: 8 July – 14 August

In Thunder Bay, eggplant: sow for seedlings from 18 April to 15 June; plant into a greenhouse from 17 June to 14 August; plant out into open ground from 8 July to 14 August.

Eggplant in Thunder Bay: soil, season and weather

In Thunder Bay the soil, not frost, sets the date: the last frost is over around 11 May, but the top 7 cm of soil reaches 18 °C — the minimum on the eggplant card — only around 8 July, 58 days later. 107 days separate planting out (8 July) from the first autumn frost (23 October); the card's 70 days to the first harvest leave 37 for picking, so a start 5 weeks late would still fit.

Last spring frost	11 May
Top 7 cm of soil at 18 °C	8 July, 58 days after the last frost
Into an unheated greenhouse	17 June – 14 August; June outside: 10.4 °C at night, 19.9 °C by day; card 21–29 °C
First autumn frost	23 October, 107 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	16 September – 23 October
Days left for picking	37
Daylight	14:55 on 9 May, 15:55 on 8 July
Watering outdoors when fruiting (card)	every 3 days; the driest month, August, has 11 rainy days

The same dates in Thunder Bay hold for Cucumber, Bell Pepper, Zucchini, Pumpkin and Watermelon.

Eggplant in Thunder Bay: care after planting

Planted on 8 July: in the first weeks water every 4 days.

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

8 July — feed: balanced (NPK)
5 August — feed: nitrogen

Pests and diseases of eggplant 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 Thunder Bay during the eggplant season

No month of the season averages above the eggplant card's 21–29 °C by day; the warmest, July, averages 23.6 °C. Months that stay below 21 °C even by day on average: September (18.2 °C) and October (10.5 °C). Nights average below 21 °C in every month of the season, from 4.2 °C to 14.4 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
July	23.6	14.4	74	11	15:44
August	22.3	14.2	63	11	14:23
September	18.2	10.9	86	11	12:38
October	10.5	4.2	71	10	10:54

ERA5 2016–2025, Open-Meteo

Eggplant in nearby cities

All the nearest cities on our list plant eggplant earlier than Thunder Bay; the closest date is in Duluth, 10 days earlier.

City	Distance	Date	Difference
Duluth	279 km	28 June – 8 July	10 days earlier
Green Bay	439 km	27 May – 10 July	42 days earlier
Minneapolis	487 km	28 May – 4 July	41 days earlier
Traverse City	488 km	5 June – 20 July	33 days earlier
Grand Forks	584 km	5 June – 26 June	33 days earlier
Fargo	589 km	31 May – 26 June	38 days earlier

Where to buy eggplant plants and seeds near Thunder Bay

Buy plants ready to set out from 8 July to 14 August (from 17 June to 14 August for an unheated greenhouse); seed for raising your own is sown from 18 April to 15 June. Within 15 km of Thunder Bay OpenStreetMap lists 2 garden centres and 1 market (collected 20 October 2026).

Goods & Co. — market
Red River Road 251 · 7 km · goodscomarket.ca
Trevisanutto's Garden Centre — garden centre
7 km
Creekside Nursery — garden centre
7 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