When to plant tomatoes in New Haven: 17 May – 23 July

In New Haven, tomato: sow for seedlings from 5 March to 1 June; plant into a greenhouse from 26 April to 23 July; plant out into open ground from 17 May to 23 July. For plants and seeds, the places nearby include Shoreline Nursery (garden centre, 7 km) and Q-Gardens (garden centre, 12 km); addresses and opening hours are below.

Tomato in New Haven: soil, season and weather

In New Haven the soil, not frost, sets the date: the last frost is over around 6 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 17 May, 41 days later.

Last spring frost	6 April
Top 7 cm of soil at 15 °C	17 May, 41 days after the last frost
Into an unheated greenhouse	26 April – 23 July; April outside: 5.1 °C at night, 14.2 °C by day; card 16–27 °C
First autumn frost	12 November, 179 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	26 July – 1 October
Days left for picking	109
Daylight	12:24 on 26 March, 14:33 on 17 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, June, has 10 rainy days

Tomato in New Haven: care after planting

Planted on 17 May: in the first weeks water every 4 days.

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

17 May — feed: balanced (NPK)
14 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 New Haven during the tomato season

Days average above the tomato card's 16–27 °C in July (28.2 °C) and August (27.1 °C). Months that stay below 16 °C even by day on average: November (11.5 °C). Nights average below 16 °C in May, June and September–November (3.5–15.9 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	19.4	10.5	117	13	14:29
June	24.9	15.9	81	10	15:08
July	28.2	20.1	121	12	14:53
August	27.1	19.2	103	12	13:52
September	23.6	15.8	118	10	12:31
October	18.2	10.4	125	11	11:09
November	11.5	3.5	87	8	9:53

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around New Haven, New York is 14 days earlier and Worcester (United States) 3 days later.

City	Distance	Date	Difference
Hartford	54 km	19 May – 19 July	2 days later
New York	113 km	3 May – 31 July	14 days earlier
Providence	138 km	17 May – 19 July	same day
Worcester (United States)	141 km	20 May – 19 July	3 days later
Albany	164 km	19 May – 17 July	2 days later
Boston	193 km	19 May – 24 July	2 days later

Where to buy tomato plants and seeds near New Haven

Buy plants ready to set out from 17 May to 23 July (from 26 April to 23 July for an unheated greenhouse); seed for raising your own is sown from 5 March to 1 June. Within 15 km of New Haven OpenStreetMap lists 5 garden centres, 1 plant nursery, 1 market and 3 farm shops (collected 28 October 2026).

Shoreline Nursery — garden centre
South End Road 9, 06512 East Haven · 7 km
Q-Gardens — garden centre
Boston Post Road 1546, 06461 Milford · 12 km
Van Wilgen's Garden Center — garden centre
Valley Road 51, 06471 North Branford · 13 km
Shelton Farmer's Market — market
Canal Street East 100, 06484 Shelton · 14 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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