When to plant zucchini in Flagstaff: 12 May – 4 August

In Flagstaff, zucchini: sow for seedlings from 31 March to 14 July; plant into a greenhouse from 21 April to 4 August; plant out into open ground from 12 May to 4 August.

Zucchini in Flagstaff: soil, season and weather

In Flagstaff frost, not soil, sets the date: the top 7 cm of soil warms to 18 °C — the minimum on the zucchini card — around 30 April, 5 days before the last frost on 5 May, so planting waits only for the week after that frost.

Last spring frost	5 May
Top 7 cm of soil at 18 °C	30 April, 5 days before the last frost
First autumn frost	21 October, 162 days after the start
Days in the bed to the first harvest (card)	36
First harvest, if planted in this window	17 June – 9 September
Days left for picking	126
Daylight	13:16 on 21 April, 13:55 on 12 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, June, has 3 rainy days

The same dates in Flagstaff hold for Tomato, Cucumber, Bell Pepper, Eggplant, Pumpkin and Watermelon.

Zucchini in Flagstaff: care after planting

Planted on 12 May: in the first weeks water every 4 days.

Pests and diseases of zucchini to watch for:

Weather in Flagstaff during the zucchini season

About 193 mm of rain falls in the season; June is the driest month (15 mm) and July the wettest (53 mm).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	21.4	7	23	6	14:00
June	28.4	13.7	15	3	14:31
July	29.7	16.5	53	10	14:19
August	27.8	15.3	51	10	13:30
September	24.7	12.1	27	5	12:26
October	18.4	6	24	4	11:20

ERA5 2016–2025, Open-Meteo

Zucchini in nearby cities

All the nearest cities on our list plant zucchini earlier than Flagstaff; the closest date is in Grand Junction, 6 days earlier.

City	Distance	Date	Difference
Phoenix	197 km	23 February – 12 October	78 days earlier
Tucson	335 km	7 March – 1 October	66 days earlier
Las Vegas	336 km	1 April – 25 September	41 days earlier
Albuquerque	452 km	18 April – 23 August	24 days earlier
Grand Junction	512 km	6 May – 10 August	6 days earlier
Santa Fe (United States)	518 km	3 May – 9 August	9 days earlier

Where to buy zucchini plants and seeds near Flagstaff

Buy plants ready to set out from 12 May to 4 August (from 21 April to 4 August for an unheated greenhouse); seed for raising your own is sown from 31 March to 14 July. Within 15 km of Flagstaff OpenStreetMap lists 1 plant nursery and 1 market (collected 28 October 2026).

Sprouts Farmers Market — market
South Riordan Ranch Street 1540, 86001 Flagstaff · Mon–Sun 07:00–22:00 · 4 km · sprouts.com
Viola's Flower Garden — plant nursery
8 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