When to plant cucumbers in Idaho Falls: 4 June – 30 July

In Idaho Falls, cucumber: sow for seedlings from 16 April to 2 July; plant into a greenhouse from 14 May to 30 July; plant out into open ground from 4 June to 30 July.

Cucumber in Idaho Falls: soil, season and weather

In Idaho Falls the soil, not frost, sets the date: the last frost is over around 11 May, but the top 7 cm of soil reaches 18 °C — the minimum on the cucumber card — only around 4 June, 24 days later.

Last spring frost	11 May
Top 7 cm of soil at 18 °C	4 June, 24 days after the last frost
Into an unheated greenhouse	14 May – 30 July; May outside: 5.5 °C at night, 20.6 °C by day; card 18–25 °C
First autumn frost	14 October, 132 days after the start
Days in the bed to the first harvest (card)	34
First harvest, if planted in this window	8 July – 2 September
Days left for picking	98
Daylight	14:23 on 7 May, 15:15 on 4 June
Watering outdoors when fruiting (card)	every 2 days; the driest month, July, has 1 rainy day

The same dates in Idaho Falls hold for Bell Pepper, Eggplant, Zucchini, Pumpkin and Watermelon.

Cucumber in Idaho Falls: care after planting

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

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

11 June — feed: nitrogen

Pests and diseases of cucumber 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 Idaho Falls during the cucumber season

No month of the season averages above the cucumber card's 18–35 °C by day; the warmest, July, averages 32.9 °C. Months that stay below 18 °C even by day on average: October (15.3 °C). Nights average below 18 °C in every month of the season, from 2.4 °C to 15.7 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	27.3	11.2	21	5	15:24
July	32.9	15.7	5	1	15:07
August	30.9	14.2	14	3	14:00
September	25.2	9.5	27	5	12:33
October	15.3	2.4	36	7	11:05

ERA5 2016–2025, Open-Meteo

Cucumber in nearby cities

Around Idaho Falls, Boise is 28 days earlier and Helena 29 days later.

City	Distance	Date	Difference
Salt Lake City	305 km	19 May – 11 August	16 days earlier
Boise	336 km	7 May – 12 August	28 days earlier
Helena	345 km	3 July – 19 July	29 days later
Billings	377 km	2 June – 30 July	2 days earlier
Missoula	406 km	30 June – 22 July	26 days later
Elko	425 km	20 May – 29 July	15 days earlier

Where to buy cucumber plants and seeds near Idaho Falls

Buy plants ready to set out from 4 June to 30 July (from 14 May to 30 July for an unheated greenhouse); seed for raising your own is sown from 16 April to 2 July. Within 15 km of Idaho Falls OpenStreetMap lists 4 garden centres, 3 farm-supply shops, 2 plant nurseries, 2 markets and 1 farm shop (collected 28 October 2026).

House Plants of Idaho Falls — garden centre
1 km
Walmart Garden Center — garden centre
4 km
Eagle Rock Nursery — plant nursery
2 km
Sunnyside Gardens — plant nursery
6 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