When to plant watermelons in Eugene: 19 June – 20 July

In Eugene, watermelon: sow for seedlings from 1 May to 22 June; plant into a greenhouse from 29 May to 20 July; plant out into open ground from 19 June to 20 July.

Watermelon in Eugene: soil, season and weather

In Eugene the soil, not frost, sets the date: the last frost is over around 15 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 19 June, 65 days later.

Last spring frost	15 April
Top 7 cm of soil at 18 °C	19 June, 65 days after the last frost
Into an unheated greenhouse	29 May – 20 July; May outside: 7.1 °C at night, 20.1 °C by day; card 18–35 °C
First autumn frost	29 October, 132 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	17 August – 17 September
Days left for picking	73
Daylight	14:59 on 22 May, 15:30 on 19 June
Watering outdoors when fruiting (card)	every 5 days; the driest month, July, has 1 rainy day

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

Watermelon in Eugene: care after planting

Planted on 19 June: in the first weeks water every 5 days.

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

19 June — 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 Eugene during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 29.9 °C. Nights average below 18 °C in every month of the season, from 6.4 °C to 12.7 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	24.1	9.9	54	7	15:28
July	29.2	12.2	5	1	15:11
August	29.9	12.7	8	2	14:03
September	25.1	10.2	64	7	12:34
October	18	6.4	132	12	11:04

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Eugene, Redding is 52 days earlier and Olympia 7 days later.

City	Distance	Date	Difference
Salem	98 km	6 June – 8 August	13 days earlier
Portland	166 km	17 June – 13 August	2 days earlier
Medford	190 km	19 June – 11 July	same day
Olympia	332 km	26 June – 6 August	7 days later
Redding	390 km	28 April – 1 September	52 days earlier
Seattle	399 km	21 June – 15 August	2 days later

Where to buy watermelon plants and seeds near Eugene

Buy plants ready to set out from 19 June to 20 July (from 29 May to 20 July for an unheated greenhouse); seed for raising your own is sown from 1 May to 22 June. Within 15 km of Eugene OpenStreetMap lists 11 garden centres, 5 farm-supply shops, 4 plant nurseries, 8 markets and 4 farm shops (collected 29 October 2026).

Armitage Wholesale Nursery — plant nursery
7 km
Bloomer's Nursery — plant nursery
7 km
Mt. Pisgah Native Plant Nursery — plant nursery
12 km
Eugene Livestock Auction — farm supply
14 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