Wyoming planting calendar

When to plant arugula in Wyoming — sow, transplant & harvest dates

Wyoming is mostly USDA zone 4b (range 3a-6a). Dates below are derived from arugula's frost tolerance and Wyoming's frost window — not generic national averages.

Arugula planting timetable for Wyoming

Stage	When in Wyoming	Anchor
Direct-sow outside	late April (April 27)	28 days before the last frost (late May)
First harvest (estimate)	early June (June 6)	~40 days from direct sow

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Wyoming's climate shifts the arugula dates

Wyoming's last spring frost averages late May and first fall frost mid-September, which sets the whole planting clock. Wyoming is a high, cold, short-season state. Altitude and wind matter as much as the winter low; frost can come in any summer month at elevation. Sow early — arugula bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Arugula is one of the most cold-tolerant salad greens — direct-sow 3-5 weeks before the last spring frost; it germinates reliably in soil as cool as 7 °C and seedlings survive light frost. It bolts quickly once daytime temperatures exceed 24 °C, turning leaves peppery-bitter, so succession-sow every 2 weeks and switch to heat-tolerant varieties (e.g. 'Astro') for late-spring runs. In zones 7–11, grow it as a fall and winter crop instead.

Frost-risk note

Don't plant before late May — a hard freeze can still set young plants back. In the high mountain basins like Jackson Hole (zone 3a) the safe date runs a week or two later.

Regional variation within Wyoming

the high mountain basins like Jackson Hole (zone 3a) runs roughly 1-2 weeks behind the state average; the lower southeast plains near Cheyenne (zone 6a) can plant 1-2 weeks earlier.

Cheyenne — USDA zone 5b
Casper — USDA zone 5a
Jackson — USDA zone 4a
Sheridan — USDA zone 5a

What else to plant in Wyoming around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun in cool weather; part shade in warm climates to delay bolting.
Soil temperature for germination: 7-18 °C (45-65 °F).
Spacing: 3-6 inches (8-15 cm) between plants.
Days to harvest: ~40 days from planting out.

Frequently asked questions

When is the best time to plant arugula in Wyoming?

In Wyoming (mostly USDA zone 4b), direct-sow arugula late April (before the last frost, late May), and harvest from early June. Arugula are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

What USDA zone is Wyoming?

Most of Wyoming sits in USDA hardiness zone 4b, with the state spanning roughly 3a-6a from the high mountain basins like Jackson Hole (zone 3a) to the lower southeast plains near Cheyenne (zone 6a). The last spring frost averages late May and the first fall frost mid-September.

Can you grow arugula in Wyoming?

Yes. Wyoming's dominant zone 4b supports arugula — the key is timing. Arugula are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across Wyoming?

the high mountain basins like Jackson Hole (zone 3a) runs roughly 1-2 weeks behind the state average; the lower southeast plains near Cheyenne (zone 6a) can plant 1-2 weeks earlier.

What else can I plant in Wyoming around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.