When to plant watermelons in Passo Fundo: 8 September – 8 March

In Passo Fundo, watermelon: sow for seedlings from 21 July to 9 February; plant into a greenhouse from 18 August to 8 March; plant out into open ground from 8 September to 8 March. For plants and seeds, the places nearby include Ikona - Concessionária Stara (farm supply, 4 km); addresses and opening hours are below.

Watermelon in Passo Fundo: soil, season and weather

In Passo Fundo the soil, not frost, sets the date: the last frost is over around 19 July, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 8 September, 51 days later.

Last spring frost	19 July
Top 7 cm of soil at 18 °C	8 September, 51 days after the last frost
Into an unheated greenhouse	18 August – 8 March; August outside: 10 °C at night, 20.2 °C by day; card 18–35 °C
First autumn frost	17 June, 283 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	6 November – 6 May
Days left for picking	224
Daylight	11:00 on 11 August, 11:43 on 8 September
Watering outdoors when fruiting (card)	every 5 days; the driest month, March, has 12 rainy days

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

Watermelon in Passo Fundo: care after planting

Planted on 8 September: in the first weeks water every 5 days.

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

8 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 Passo Fundo during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, January, averages 27.9 °C. Nights average below 18 °C in March–June and September–December (9.7–17.6 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
September	22.7	12.6	153	12	11:54
October	23.7	14	207	14	12:44
November	25.8	15.4	166	12	13:31
December	27.5	17.6	135	15	13:55
January	27.9	18.9	135	16	13:45
February	27.3	18.3	122	13	13:04
March	26.4	17.2	121	12	12:17
April	23.9	14.9	133	11	11:26
May	20.2	11.7	220	13	10:44
June	18.3	9.7	175	11	10:21

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Passo Fundo, Posadas is 45 days earlier and Lages 16 days later.

City	Distance	Date	Difference
Chapecó	131 km	12 September – 14 March	4 days later
Caxias do Sul	157 km	1 September – 7 March	7 days earlier
Santa Maria	209 km	14 August – 3 March	25 days earlier
Lages	210 km	24 September – 14 March	16 days later
Guarapuava	332 km	22 September – 14 March	14 days later
Posadas	358 km	from 25 July	45 days earlier

Where to buy watermelon plants and seeds near Passo Fundo

Buy plants ready to set out from 8 September to 8 March (from 18 August to 8 March for an unheated greenhouse); seed for raising your own is sown from 21 July to 9 February. Within 15 km of Passo Fundo OpenStreetMap lists 2 farm-supply shops and 2 markets (collected 27 October 2026).

Ikona - Concessionária Stara — farm supply
Estrada do Trigo 543, 99052-160 Passo Fundo · 4 km · ikona.com.br
Feira Ecológica — market
Sat 06:00–12:00 · 1 km
Zanatta — farm supply
4 km
Feira do Produtor — 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.

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