When to plant tomatoes in Trieste: 18 May – 8 August

In Trieste, tomato: sow for seedlings from 6 March to 17 June; plant into a greenhouse from 27 April to 8 August; plant out into open ground from 18 May to 8 August. For plants and seeds, the places nearby include Biogeste Vivai & Giardini (garden centre, 2 km) and AgroSosič (garden centre, 4 km); addresses and opening hours are below.

Tomato in Trieste: soil, season and weather

In Trieste the soil, not frost, sets the date: the last frost is over around 19 March, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 18 May, 60 days later.

Last spring frost	19 March
Top 7 cm of soil at 15 °C	18 May, 60 days after the last frost
Into an unheated greenhouse	27 April – 8 August; April outside: 6.6 °C at night, 14.9 °C by day; card 16–27 °C
First autumn frost	28 November, 194 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	27 July – 17 October
Days left for picking	124
Daylight	12:30 on 27 March, 15:01 on 18 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, June, has 9 rainy days

Tomato in Trieste: care after planting

Planted on 18 May: in the first weeks water every 4 days.

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

18 May — feed: balanced (NPK)
15 June — 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 Trieste during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, August, averages 26.9 °C. Months that stay below 16 °C even by day on average: November (11.2 °C). Nights average below 16 °C in May and September–November (5.6–14.1 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	18.5	10.8	160	16	14:54
June	24.3	16	90	9	15:41
July	26.5	17.8	105	9	15:22
August	26.9	18.1	95	7	14:10
September	21.7	14.1	189	11	12:35
October	16.9	10	175	12	11:00
November	11.2	5.6	189	14	9:31

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Trieste, Venice is 28 days earlier and Klagenfurt 49 days later.

City	Distance	Date	Difference
Udine	63 km	29 April – 2 August	19 days earlier
Venice	115 km	20 April – 16 August	28 days earlier
Klagenfurt	115 km	6 July – 16 July	49 days later
Treviso	120 km	27 April – 3 August	21 days earlier
Padua	150 km	20 April – 8 August	28 days earlier
Zagreb	172 km	2 May – 2 August	16 days earlier

Where to buy tomato plants and seeds near Trieste

Buy plants ready to set out from 18 May to 8 August (from 27 April to 8 August for an unheated greenhouse); seed for raising your own is sown from 6 March to 17 June. Within 15 km of Trieste OpenStreetMap lists 19 garden centres, 2 farm-supply shops, 1 plant nursery, 9 markets and 3 farm shops (collected 20 October 2026).

Floricoltura / Vrtnarija Orel — garden centre
Stazione di Prosecco / Proseška Postaja 32, 34010 Sgonico / Zgonik · Mon–Sat 08:00–12:30, 14:30–18:00; public holidays closed · 8 km · flor-orel.com
AgroSosič — garden centre
Via di Basovizza 2, 34151 Trieste · Tue–Sat 08:30–13:00, 15:00–18:00; Mar Sun[–1]–Oct Sun[–1]: Tue–Sat 08:30–13:00, 15:30–19:00; public holidays closed · 4 km · agrososic.eu
Ever Green — garden centre
Via Dragotin Kette / Kettejeva ulica 13a, 34149 Trieste · Mon 08:30–13:30, Tue–Sat 08:30–13:30, 15:30–19:00; public holidays closed · 7 km · agroevergreen.it
Biogeste Vivai & Giardini — garden centre
Via Brandesia 13, 34128 Trieste · Mon–Sat 08:30–19:00; public holidays closed · 2 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