When to plant watermelons in Trenton: 21 May – 3 August

In Trenton, watermelon: sow for seedlings from 2 April to 6 July; plant into a greenhouse from 30 April to 3 August; plant out into open ground from 21 May to 3 August. For plants and seeds, the places nearby include McKithen Produce (farm shop, 2 km) and Fiallo's Produce Store (farm shop, 3 km); addresses and opening hours are below.

Watermelon in Trenton: soil, season and weather

In Trenton the soil, not frost, sets the date: the last frost is over around 6 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 21 May, 45 days later.

Last spring frost	6 April
Top 7 cm of soil at 18 °C	21 May, 45 days after the last frost
Into an unheated greenhouse	30 April – 3 August; April outside: 6.3 °C at night, 17.2 °C by day; card 18–35 °C
First autumn frost	12 November, 175 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	19 July – 1 October
Days left for picking	116
Daylight	13:35 on 23 April, 14:34 on 21 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 8 rainy days

The same dates in Trenton hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.

Watermelon in Trenton: care after planting

Planted on 21 May: in the first weeks water every 5 days.

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

21 May — feed: balanced (NPK)

Pests and diseases of watermelon 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 Trenton during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 31 °C. Months that stay below 18 °C even by day on average: November (12.8 °C). Nights average below 18 °C in May, June and September–November (3.8–17 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	22.3	11.7	128	13	14:23
June	27.9	17	98	12	15:01
July	31	20.8	135	14	14:46
August	29.3	19.7	117	12	13:48
September	25.8	16.4	109	10	12:30
October	19.9	10.6	96	10	11:11
November	12.8	3.8	79	8	9:59

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Trenton, Atlantic City is 16 days earlier and Harrisburg 4 days later.

City	Distance	Date	Difference
Philadelphia	45 km	14 May – 2 August	7 days earlier
Allentown	73 km	23 May – 25 July	2 days later
New York	84 km	21 May – 11 August	same day
Atlantic City	100 km	5 May – 13 August	16 days earlier
Dover	134 km	11 May – 17 August	10 days earlier
Harrisburg	179 km	25 May – 2 August	4 days later

Where to buy watermelon plants and seeds near Trenton

Buy plants ready to set out from 21 May to 3 August (from 30 April to 3 August for an unheated greenhouse); seed for raising your own is sown from 2 April to 6 July. Within 15 km of Trenton OpenStreetMap lists 6 garden centres, 1 farm-supply shop, 3 plant nurseries, 5 markets and 3 farm shops (collected 28 October 2026).

Milk House Farm Market — market
Slack Road 1118, Newtown · 15 km
McKithen Produce — farm shop
Grant Avenue 50, 08638 Trenton · 2 km · mckitchen-produce.hub.biz
Fiallo's Produce Store — farm shop
South Broad Street 1023, 08611 Trenton · 3 km
SiteOne Landscape Supply — garden centre
8 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