When to plant tomatoes in London (Canada): 19 May – 18 July

In London (Canada), tomato: sow for seedlings from 7 March to 27 May; plant into a greenhouse from 28 April to 18 July; plant out into open ground from 19 May to 18 July. For plants and seeds, the places nearby include Millar Berry Farms (farm shop, 11 km) and The Living Centre (farm shop, 15 km); addresses and opening hours are below.

Tomato in London (Canada): soil, season and weather

In London (Canada) the soil, not frost, sets the date: the last frost is over around 28 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 19 May, 21 days later.

Last spring frost	28 April
Top 7 cm of soil at 15 °C	19 May, 21 days after the last frost
Into an unheated greenhouse	28 April – 18 July; April outside: 2.2 °C at night, 12.6 °C by day; card 16–27 °C
First autumn frost	7 November, 172 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	28 July – 26 September
Days left for picking	102
Daylight	12:31 on 28 March, 14:46 on 19 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, September, has 9 rainy days

Tomato in London (Canada): care after planting

Planted on 19 May: in the first weeks water every 4 days.

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

19 May — feed: balanced (NPK)
16 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 London (Canada) during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, July, averages 27 °C. Months that stay below 16 °C even by day on average: October (15.9 °C) and November (7.9 °C). Nights average below 16 °C in May, June and September–November (1.1–14.6 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	19.7	9	82	12	14:38
June	25	14.6	90	11	15:20
July	27	17.4	103	12	15:04
August	25.7	16.8	98	13	13:58
September	22.8	13.8	62	9	12:33
October	15.9	7.9	97	13	11:06
November	7.9	1.1	73	13	9:45

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around London (Canada), Windsor is 5 days earlier and Kitchener 3 days later.

City	Distance	Date	Difference
Kitchener	77 km	22 May – 6 July	3 days later
Hamilton	116 km	19 May – 18 July	same day
Erie	133 km	20 May – 30 July	1 day later
Windsor	165 km	14 May – 18 July	5 days earlier
Detroit	165 km	14 May – 18 July	5 days earlier
Toronto	167 km	20 May – 10 July	1 day later

Where to buy tomato plants and seeds near London (Canada)

Buy plants ready to set out from 19 May to 18 July (from 28 April to 18 July for an unheated greenhouse); seed for raising your own is sown from 7 March to 27 May. Within 15 km of London (Canada) OpenStreetMap lists 5 garden centres, 3 markets and 2 farm shops (collected 20 October 2026).

Covent Garden Market — market
King Street 130, N6A 1C5 London · Tue–Sat 09:00–19:00; Sun 10:00–17:00 · 2 km · coventmarket.com
The Market — market
King Street 900, N5Y 5P8 London · 1 km · westernfairdistrict.com
Millar Berry Farms — farm shop
Longwoods Road 7375, N6P1L2 London · 11 km · millarberryfarms.com
The Living Centre — farm shop
Bells Road 5871, N6P 1P3 · 15 km · thelivingcentre.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.

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