When to plant watermelons in Tarija: 11 September – 3 March

In Tarija, watermelon: sow for seedlings from 24 July to 4 February; plant into a greenhouse from 21 August to 3 March; plant out into open ground from 11 September to 3 March.

Watermelon in Tarija: soil, season and weather

In Tarija the soil, not frost, sets the date: the last frost is over around 27 August, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 11 September, 15 days later.

Last spring frost	27 August
Top 7 cm of soil at 18 °C	11 September, 15 days after the last frost
Into an unheated greenhouse	21 August – 3 March; August outside: 6.4 °C at night, 22.7 °C by day; card 18–35 °C
First autumn frost	12 June, 275 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	9 November – 1 May
Days left for picking	216
Daylight	11:21 on 14 August, 11:52 on 11 September
Watering outdoors when fruiting (card)	every 5 days; the driest month, June, has 2 rainy days

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

Watermelon in Tarija: care after planting

Planted on 11 September: in the first weeks water every 5 days.

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

11 September — 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 Tarija during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, October, averages 25.2 °C. Nights average below 18 °C in every month of the season, from 6.4 °C to 14.3 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
September	24.8	8.8	24	6	11:57
October	25.2	11.1	72	14	12:34
November	24.6	12.7	144	19	13:08
December	23.8	13.9	271	25	13:26
January	23.6	14.3	297	25	13:18
February	22.9	13.9	255	24	12:48
March	22.2	13.1	204	23	12:14
April	21.3	11.4	74	13	11:36
May	20.2	8.2	15	5	11:06
June	20.9	6.4	6	2	10:50

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Tarija, Sucre is 21 days earlier and Potosí 78 days later.

City	Distance	Date	Difference
Potosí	241 km	28 November – 5 December	78 days later
Sucre	283 km	21 August – 21 March	21 days earlier
San Salvador de Jujuy	301 km	22 September – 15 March	11 days later
Salta	369 km	26 September – 20 March	15 days later
Calama	445 km	from 9 September	2 days earlier
Oruro	467 km	19 October – 19 January	38 days later

Where to buy watermelon plants and seeds near Tarija

Buy plants ready to set out from 11 September to 3 March (from 21 August to 3 March for an unheated greenhouse); seed for raising your own is sown from 24 July to 4 February. Within 15 km of Tarija OpenStreetMap lists 15 markets (collected 28 October 2026).

MERCADO BOLIVAR — market
1 km
Mercado Campesino — market
2 km
Mercado Guadalquivir — market
0 km
avaroa — market
1 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