When to plant watermelons in Ushuaia

In Ushuaia, watermelon: sow for seedlings from 31 October; plant into a greenhouse from 28 November; plant out into open ground from 19 December. The frost-free season here is shorter than the 59 days the crop needs from planting to harvest (by its card): grow it in a greenhouse or choose an early variety.

Watermelon in Ushuaia: soil, season and weather

In the median year the top 7 cm of soil in Ushuaia does not reach 18 °C, the minimum on the watermelon card, before August; the date follows the last frost (12 December), and the bed stays cooler than the card asks. Between planting out (19 December) and the first autumn frost (26 January) there are 38 days, 21 fewer than the card's 59 to the first harvest; in an unheated greenhouse, three weeks earlier, 0 would be left to spare.

Last spring frost	12 December
Into an unheated greenhouse	from 28 November; November outside: 2 °C at night, 9 °C by day; card 18–35 °C
First autumn frost	26 January, 38 days after the start
Days in the bed to the first harvest (card)	59
Days left for picking	-21
Daylight	16:21 on 21 November, 17:19 on 19 December
Watering outdoors when fruiting (card)	every 5 days; the driest month, December, has 22 rainy days

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

Watermelon in Ushuaia: care after planting

Planted on 19 December: in the first weeks water every 5 days.

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

19 December — 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 Ushuaia during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, January, averages 11 °C. Months that stay below 18 °C even by day on average: December (10.2 °C) and January (11 °C). Nights average below 18 °C in every month of the season, from 3.3 °C to 4.3 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
December	10.2	3.3	104	22	17:16
January	11	4.3	116	23	16:42

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Ushuaia, Trelew is 58 days earlier and Puerto Montt 10 days later.

City	Distance	Date	Difference
Punta Arenas	250 km	4 November – 27 December	45 days earlier
Río Gallegos	360 km	12 December – 26 December	7 days earlier
Comodoro Rivadavia	997 km	1 November – 12 February	48 days earlier
Coyhaique	1,061 km	from 10 December	9 days earlier
Trelew	1,304 km	22 October – 17 February	58 days earlier
Puerto Montt	1,522 km	29 December – 25 February	10 days later

Where to buy watermelon plants and seeds near Ushuaia

Buy plants ready to set out from 19 December (from 28 November for an unheated greenhouse); seed for raising your own is sown from 31 October. Within 15 km of Ushuaia OpenStreetMap lists 3 markets (collected 27 October 2026).

Mar de Cobos — market
2 km
Champita — market
2 km
Mercado De la Costa — market
6 km

Questions