When to plant tomatoes in Allentown: 3 May – 14 July

In Allentown, tomato: sow for seedlings from 19 February to 23 May; plant into a greenhouse from 12 April to 14 July; plant out into open ground from 3 May to 14 July. For plants and seeds, the places nearby include Lehigh Valley Home & Garden Center (garden centre, 6 km) and Herbein's Garden Center (garden centre, 10 km); addresses and opening hours are below.

Tomato in Allentown: soil, season and weather

In Allentown the soil, not frost, sets the date: the last frost is over around 15 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 3 May, 18 days later.

Last spring frost	15 April
Top 7 cm of soil at 15 °C	3 May, 18 days after the last frost
Into an unheated greenhouse	12 April – 14 July; April outside: 5.3 °C at night, 16.3 °C by day; card 16–27 °C
First autumn frost	3 November, 184 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	12 July – 22 September
Days left for picking	114
Daylight	11:45 on 12 March, 14:00 on 3 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, November, has 9 rainy days

Tomato in Allentown: care after planting

Planted on 3 May: in the first weeks water every 4 days.

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

3 May — feed: balanced (NPK)
31 May — 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 Allentown during the tomato season

Days average above the tomato card's 16–27 °C in July (30.2 °C) and August (28.2 °C). Months that stay below 16 °C even by day on average: November (11.3 °C). Nights average below 16 °C in May, June and September–November (2.4–15.9 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	21.6	10.8	120	13	14:25
June	26.9	15.9	101	12	15:04
July	30.2	19.6	125	14	14:49
August	28.2	18.3	127	13	13:49
September	24.9	14.9	106	10	12:30
October	18.7	9.2	93	9	11:11
November	11.3	2.4	80	9	9:57

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

3 of the nearest cities share Allentown's date.

City	Distance	Date	Difference
Trenton	73 km	3 May – 23 July	same day
Philadelphia	77 km	29 April – 22 July	4 days earlier
Harrisburg	124 km	3 May – 22 July	same day
New York	125 km	3 May – 31 July	same day
Dover	160 km	17 April – 6 August	16 days earlier
Atlantic City	165 km	24 April – 2 August	9 days earlier

Where to buy tomato plants and seeds near Allentown

Buy plants ready to set out from 3 May to 14 July (from 12 April to 14 July for an unheated greenhouse); seed for raising your own is sown from 19 February to 23 May. Within 15 km of Allentown OpenStreetMap lists 14 garden centres, 1 plant nursery, 6 markets and 7 farm shops (collected 29 October 2026).

Herbein's Garden Center — garden centre
Chestnut Street 4301, 18049 Emmaus · Mon–Fri 08:00–17:00; Sat 08:00–17:00; Sun 09:00–17:00 · 10 km · herbeins.com
4 Seasons Garden Center — garden centre
Hamilton Boulevard 9005, 18031 Breinigsville · Mon–Fri 08:00–17:00; Sat 08:00–16:00 · 15 km · 4-seasonsgardencenter.net
Turf Pro, Inc. — garden centre
Chestnut Street 6591, 18092 Zionsville · Mon–Fri 08:00–16:30 · 15 km · turfprolv.com
Lehigh Valley Home & Garden Center — garden centre
Crackersport Road 4178, 18104 Allentown · 6 km · lvhgc.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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