When to plant watermelons in Jaén: 26 April – 7 September

In Jaén, watermelon: sow for seedlings from 8 March to 10 August; plant into a greenhouse from 5 April to 7 September; plant out into open ground from 26 April to 7 September.

Watermelon in Jaén: soil, season and weather

In Jaén the soil, not frost, sets the date: the last frost is over around 9 February, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 26 April, 76 days later.

Last spring frost	9 February
Top 7 cm of soil at 18 °C	26 April, 76 days after the last frost
Into an unheated greenhouse	5 April – 7 September; April outside: 10.1 °C at night, 21.1 °C by day; card 18–35 °C
First autumn frost	17 December, 235 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	24 June – 5 November
Days left for picking	176
Daylight	12:29 on 29 March, 13:34 on 26 April
Watering outdoors when fruiting (card)	every 5 days; the driest month, July, has 1 rainy day

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

Watermelon in Jaén: care after planting

Planted on 26 April: in the first weeks water every 5 days.

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

26 April — 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 Jaén during the watermelon season

Days average above the watermelon card's 18–35 °C in July (36.4 °C) and August (36 °C). Months that stay below 18 °C even by day on average: November (17.4 °C) and December (14.8 °C). Nights average below 18 °C in April, May and September–December (6–17.8 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
April	21.1	10.1	59	9	13:09
May	26.1	13.7	35	5	14:12
June	31.7	18.4	15	3	14:46
July	36.4	21.9	2	1	14:32
August	36	22	5	1	13:39
September	30.1	17.8	22	4	12:28
October	25.2	14	47	6	11:16
November	17.4	8.6	63	9	10:09
December	14.8	6	50	8	9:34

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Jaén, Écija is 17 days earlier and Granada 35 days later.

City	Distance	Date	Difference
Úbeda	46 km	7 May – 24 August	11 days later
Granada	68 km	31 May – 17 August	35 days later
Córdoba (Spain)	87 km	21 April – 18 September	5 days earlier
Écija	116 km	9 April – 18 September	17 days earlier
Ciudad Real	136 km	7 May – 19 August	11 days later
Lorca	184 km	18 April – 5 September	8 days earlier

Where to buy watermelon plants and seeds near Jaén

Buy plants ready to set out from 26 April to 7 September (from 5 April to 7 September for an unheated greenhouse); seed for raising your own is sown from 8 March to 10 August. Within 15 km of Jaén OpenStreetMap lists 2 garden centres, 3 farm-supply shops, 8 markets and 1 farm shop (collected 27 October 2026).

Mercado de Abastos — market
10 km
Mercado de Abastos — market
11 km
Mercado Municipal — market
15 km
Mercadillo (romería) — market
7 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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