When to plant in Wyoming
Wyoming spans USDA hardiness zones 2-7. Average last spring frost: late May. Average first fall frost: early September. This calendar is anchored to University of Wyoming Extension's recommendations, with timing adjusted for the dominant climate zone of the state.
Wyoming at a glance
| USDA hardiness zones | 2-7 |
| Region | Mountain West |
| Average last spring frost | late May |
| Average first fall frost | early September |
| Primary Extension service | University of Wyoming Extension |
What grows particularly well in Wyoming
These are the crops, ornamentals, and trees University of Wyoming Extension highlights as well-suited to Wyoming's climate:
- Russian sage
- peony
- aspen
- potato
- blanketflower
- wheat
Wyoming planting calendar
Dates are approximate and based on the dominant USDA zone for the state. For zone-specific timing, use the zone finder by ZIP code and frost date lookup tools.
Spring planting (after last frost: late May)
Cool-season vegetables (start 2-6 weeks before last frost outdoors): lettuce, spinach, peas, radishes, carrots, beets, kale, broccoli transplants, cabbage transplants.
Warm-season vegetables (after last frost, soil 60F+): tomato transplants, pepper transplants, beans (direct sow), cucumbers, squash, melons. See the seed starting timeline tool for indoor start dates.
Annual flowers (after last frost): zinnia, marigold, cosmos, sunflower, nasturtium.
Perennials, shrubs, trees: Plant in spring after soil thaws but before summer heat. Best window in Wyoming: 4-6 weeks after last frost.
Summer (June - August)
Maintenance season for most Wyoming gardens. Mulch heavily, water deeply (1 inch per week), pinch back mums for fall bloom, hand-pull weeds, harvest summer vegetables. Plant fall vegetable starts indoors by mid-July.
Fall planting (before first frost: early September)
Cool-season vegetables (6-8 weeks before first frost): lettuce, spinach, radish, kale, broccoli, cabbage transplants. Per Penn State Extension, fall vegetable production can equal or exceed spring production with proper timing.
Spring-flowering bulbs: tulip, daffodil, allium, crocus, hyacinth. Plant 4-6 weeks before ground freezes. In Wyoming: typically October-November.
Perennials, shrubs, trees: Fall is the best planting season for woody plants in most of Wyoming - cooler temperatures + autumn rains reduce transplant stress. Plant 6+ weeks before first hard freeze.
Garlic: Plant cloves in October-November. Harvest the following July.
Winter (December - February)
Most of Wyoming is in dormancy. Tasks: order seeds, plan next year, dormant prune fruit trees (February), order bare-root plants for spring delivery. Avoid foot traffic on frozen lawns.
Common Wyoming challenges
Extreme cold and short season at altitude; chinook winds; alkaline soils; deer and antelope pressure; intense UV; hailstorms. For region-specific guidance, see our Mountain West regional gardening guide.
Where to get Wyoming-specific advice
The most reliable source for local growing advice is your county Extension office. University of Wyoming Extension has county offices that provide free soil testing, plant disease diagnosis, and growing recommendations specific to your microclimate.
Visit University of Wyoming Extension for the office nearest you.
Related tools and guides
- Find your USDA zone by ZIP code
- Look up your average frost dates
- Seasonal care calendar by zone
- Seed starting timeline calculator
- Mountain West regional gardening guide