When to plant cucumbers in Fort Collins: 7 June – 6 August

In Fort Collins, cucumber: sow for seedlings from 19 April to 9 July; plant into a greenhouse from 17 May to 6 August; plant out into open ground from 7 June to 6 August. For plants and seeds, the places nearby include Horsetooth Stem and Roots (garden centre, 4 km) and Creekside Garden Center (garden centre, 7 km); addresses and opening hours are below.

Cucumber in Fort Collins: soil, season and weather

In Fort Collins the soil, not frost, sets the date: the last frost is over around 25 April, but the top 7 cm of soil reaches 18 °C — the minimum on the cucumber card — only around 7 June, 43 days later.

Last spring frost	25 April
Top 7 cm of soil at 18 °C	7 June, 43 days after the last frost
Into an unheated greenhouse	17 May – 6 August; May outside: 6.4 °C at night, 21.1 °C by day; card 18–25 °C
First autumn frost	21 October, 136 days after the start
Days in the bed to the first harvest (card)	34
First harvest, if planted in this window	11 July – 9 September
Days left for picking	102
Daylight	14:15 on 10 May, 14:58 on 7 June
Watering outdoors when fruiting (card)	every 2 days; the driest month, October, has 4 rainy days

The same dates in Fort Collins hold for Bell Pepper, Eggplant, Zucchini, Pumpkin and Watermelon.

Cucumber in Fort Collins: care after planting

Planted on 7 June: in the first weeks water every 4 days.

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

14 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 Fort Collins during the cucumber season

No month of the season averages above the cucumber card's 18–35 °C by day; the warmest, July, averages 31.6 °C. Nights average below 18 °C in every month of the season, from 3.8 °C to 16.2 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	28.4	12.7	40	8	15:03
July	31.6	16.2	37	7	14:48
August	30.5	15.2	34	7	13:49
September	27.7	11.2	22	4	12:30
October	18.8	3.8	20	4	11:11

ERA5 2016–2025, Open-Meteo

Cucumber in nearby cities

Around Fort Collins, Pueblo is 35 days earlier and Cheyenne 1 day later.

City	Distance	Date	Difference
Cheyenne	69 km	8 June – 29 July	1 day later
Denver	90 km	28 May – 31 July	10 days earlier
Colorado Springs	192 km	6 June – 31 July	1 day earlier
Pueblo	258 km	3 May – 13 August	35 days earlier
Grand Junction	340 km	6 May – 12 August	32 days earlier
Rapid City	420 km	6 June – 28 July	1 day earlier

Where to buy cucumber plants and seeds near Fort Collins

Buy plants ready to set out from 7 June to 6 August (from 17 May to 6 August for an unheated greenhouse); seed for raising your own is sown from 19 April to 9 July. Within 15 km of Fort Collins OpenStreetMap lists 10 garden centres, 4 farm-supply shops, 2 plant nurseries, 3 markets and 6 farm shops (collected 28 October 2026).

Plantorium — garden centre
County Road 54G 2933, 80524-1087 Fort Collins · Mon–Fri 09:00–17:00 · 10 km · plantorium.com
Walmart Garden Center — garden centre
West 65th Street 250, 80538 Loveland · 24/7 · 10 km · walmart.com
Creekside Garden Center — garden centre
North Shields Street 1224, 80524 Fort Collins · 7 km
Horsetooth Stem and Roots — garden centre
Mon–Sat 11:00–18:00; Sun 11:00–17:00 · 4 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