When to plant tomatoes in Trois-Rivières: 25 May – 9 July

In Trois-Rivières, tomato: sow for seedlings from 13 March to 18 May; plant into a greenhouse from 4 May to 9 July; plant out into open ground from 25 May to 9 July. For plants and seeds, the places nearby include Maison Chaleur et Confort (garden centre, 6 km) and RDR Grains et Semences (farm supply, 9 km); addresses and opening hours are below.

Tomato in Trois-Rivières: soil, season and weather

In Trois-Rivières the soil, not frost, sets the date: the last frost is over around 29 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 25 May, 26 days later.

Last spring frost	29 April
Top 7 cm of soil at 15 °C	25 May, 26 days after the last frost
Into an unheated greenhouse	4 May – 9 July; May outside: 7.9 °C at night, 19.2 °C by day; card 16–27 °C
First autumn frost	29 October, 157 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	3 August – 17 September
Days left for picking	87
Daylight	12:54 on 3 April, 15:20 on 25 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, September, has 9 rainy days

Tomato in Trois-Rivières: care after planting

Planted on 25 May: in the first weeks water every 4 days.

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

25 May — feed: balanced (NPK)
22 June — feed: nitrogen

Pests and diseases of tomato 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 Trois-Rivières during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, July, averages 26.2 °C. Months that stay below 16 °C even by day on average: October (14.4 °C). Nights average below 16 °C in May, June and August–October (6.3–15.9 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	19.2	7.9	93	12	14:58
June	23.6	13.7	125	14	15:47
July	26.2	17	130	15	15:27
August	24.8	15.9	131	14	14:13
September	21	12	78	9	12:36
October	14.4	6.3	117	12	10:59

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Trois-Rivières, Montreal is 4 days earlier and Saguenay 16 days later.

City	Distance	Date	Difference
Quebec City	114 km	27 May – 8 July	2 days later
Sherbrooke	116 km	27 May – 7 July	2 days later
Montreal	123 km	21 May – 12 July	4 days earlier
Burlington	213 km	26 May – 14 July	1 day later
Montpelier	231 km	29 May – 27 June	4 days later
Saguenay	257 km	10 June – 2 July	16 days later

Where to buy tomato plants and seeds near Trois-Rivières

Buy plants ready to set out from 25 May to 9 July (from 4 May to 9 July for an unheated greenhouse); seed for raising your own is sown from 13 March to 18 May. Within 15 km of Trois-Rivières OpenStreetMap lists 1 garden centre, 2 farm-supply shops, 1 market and 2 farm shops (collected 20 October 2026).

Maison Chaleur et Confort — garden centre
Boulevard Thibeau 1015, G8T 7B3 Trois-Rivières · Tue, Wed, Fri 09:00–17:30; Thu 09:00–20:00; Sat 09:00–16:00 · 6 km · maisonchaleuretconfort.com
RDR Grains et Semences — farm supply
Rang des Soixante 3680, J3T 1P4 Nicolet · 9 km · semencesrdr.com
Rovibec Agrisolutions Inc. — farm supply
Route du Port 475, J3T 1W3 Nicolet · 11 km · rovibecagrisolutions.com
Marché La Providence — market
Rue Champflour 1008, G9A 1Z7 Trois-Rivières · 1 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.

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