When to plant tomatoes in San Luis: 31 August – 2 March

In San Luis, tomato: sow for seedlings from 19 June to 10 January; plant into a greenhouse from 10 August to 2 March; plant out into open ground from 31 August to 2 March.

Tomato in San Luis: soil, season and weather

In San Luis the soil, not frost, sets the date: the last frost is over around 21 August, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 31 August, 10 days later.

Last spring frost	21 August
Top 7 cm of soil at 15 °C	31 August, 10 days after the last frost
Into an unheated greenhouse	10 August – 2 March; August outside: 6.7 °C at night, 18.3 °C by day; card 16–27 °C
First autumn frost	22 June, 296 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	9 November – 11 May
Days left for picking	226
Daylight	10:04 on 10 July, 11:22 on 31 August
Watering outdoors when fruiting (card)	every 3 days; the driest month, August, has 2 rainy days

Tomato in San Luis: care after planting

Planted on 31 August: in the first weeks water every 4 days.

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

31 August — feed: balanced (NPK)
28 September — feed: nitrogen

Pests and diseases of tomato 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 San Luis during the tomato season

Days average above the tomato card's 16–27 °C in December (28.2 °C), January (28.7 °C) and February (27.6 °C). Months that stay below 16 °C even by day on average: June (14.6 °C). Nights average below 16 °C in March–June and August–November (5.3–15.5 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
August	18.3	6.7	11	2	10:52
September	21	9.1	20	4	11:51
October	23.4	11.7	54	8	12:53
November	26.1	14.9	85	12	13:50
December	28.2	17.3	70	11	14:20
January	28.7	18.6	105	14	14:07
February	27.6	18	78	11	13:17
March	25	15.5	81	11	12:20
April	20.9	12	55	7	11:17
May	17	8.4	30	5	10:25
June	14.6	5.3	13	2	9:58

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around San Luis, San Juan is 2 days earlier and Santiago 23 days later.

City	Distance	Date	Difference
Río Cuarto	184 km	15 September – 22 February	15 days later
San Rafael	238 km	11 September – 13 February	11 days later
Mendoza	238 km	9 September – 25 February	9 days later
San Juan	284 km	29 August – 28 February	2 days earlier
Córdoba	289 km	31 August – 23 February	same day
Santiago	404 km	23 September – 26 February	23 days later

Where to buy tomato plants and seeds near San Luis

Buy plants ready to set out from 31 August to 2 March (from 10 August to 2 March for an unheated greenhouse); seed for raising your own is sown from 19 June to 10 January. Within 15 km of San Luis OpenStreetMap lists 1 plant nursery (collected 27 October 2026).

Vivero Improfop SAPEM — plant nursery
9 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