Wyoming planting calendar

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

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

Lettuce planting timetable for Wyoming

Stage	When in Wyoming	Anchor
Start seeds indoors	late April (April 27)	4 weeks before the last frost (late May)
Transplant outside	early May (May 4)	21 days before the last frost (late May)
First harvest (estimate)	late June (June 23)	~50 days from transplant

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 lettuce 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 — lettuce bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Lettuce is genuinely cold-hardy — direct-sow as soon as soil can be worked, 2-4 weeks before the last spring frost. It bolts and turns bitter in summer heat above 24 °C, so southern zones grow it as a winter and shoulder-season crop instead of in midsummer.

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, light shade in heat.
Soil temperature for germination: 10-21 °C (50-70 °F).
Spacing: 6-12 inches (15-30 cm) between plants.
Days to harvest: ~50 days from planting out.

Frequently asked questions

When is the best time to plant lettuce in Wyoming?

In Wyoming (mostly USDA zone 4b), sow lettuce indoors around late April, transplant outdoors early May (before the last frost, late May), and harvest from late June. Lettuce 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 lettuce in Wyoming?

Yes. Wyoming's dominant zone 4b supports lettuce — the key is timing. Lettuce 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.