When to plant watermelons in Hartford: 31 May – 30 July

In Hartford, watermelon: sow for seedlings from 12 April to 2 July; plant into a greenhouse from 10 May to 30 July; plant out into open ground from 31 May to 30 July.

Watermelon in Hartford: soil, season and weather

In Hartford the soil, not frost, sets the date: the last frost is over around 13 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 31 May, 48 days later.

Last spring frost	13 April
Top 7 cm of soil at 18 °C	31 May, 48 days after the last frost
Into an unheated greenhouse	10 May – 30 July; May outside: 9.9 °C at night, 20.8 °C by day; card 18–35 °C
First autumn frost	8 November, 161 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	29 July – 27 September
Days left for picking	102
Daylight	14:05 on 3 May, 14:58 on 31 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, June, has 12 rainy days

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

Watermelon in Hartford: care after planting

Planted on 31 May: in the first weeks water every 5 days.

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

31 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 Hartford during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 29.5 °C. Months that stay below 18 °C even by day on average: November (10.8 °C). Nights average below 18 °C in May, June and September–November (1.9–15.2 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	20.8	9.9	114	13	14:31
June	26.5	15.2	82	12	15:12
July	29.5	19	141	14	14:56
August	28.1	18.1	95	11	13:54
September	24.1	14.5	127	9	12:32
October	18.1	8.9	126	11	11:08
November	10.8	1.9	82	9	9:51

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

2 of the nearest cities share Hartford's date.

City	Distance	Date	Difference
New Haven	54 km	26 May – 3 August	5 days earlier
Worcester (United States)	93 km	31 May – 30 July	same day
Providence	106 km	31 May – 30 July	same day
Albany	133 km	30 May – 28 July	1 day earlier
Boston	150 km	29 May – 4 August	2 days earlier
New York	161 km	21 May – 11 August	10 days earlier

Where to buy watermelon plants and seeds near Hartford

Buy plants ready to set out from 31 May to 30 July (from 10 May to 30 July for an unheated greenhouse); seed for raising your own is sown from 12 April to 2 July. Within 15 km of Hartford OpenStreetMap lists 10 garden centres, 1 farm-supply shop, 1 plant nursery, 5 markets and 11 farm shops (collected 20 October 2026).

Barrett's Farm Stand — farm shop
12 km
Little Acres Farm Market — farm shop
13 km
Fair Weather Acres Farm Market — farm shop
14 km
Tricka Farm — farm shop
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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