What to plant in September in Wyoming
In Wyoming (WY), the average first fall frost (September 15) has passed by mid-September. The state averages 118 frost-free days a year (last frost May 20, first frost September 15; USDA zones 3a, 3b, 4a, 4b, 5a, 6a).
2 crops have a sowing or planting window this month: shallot, garlic.
Dates here come from Wyoming frost dates (last frost May 20, first frost Sep 15). For one crop in detail, see when to plant garlic, tomato or lettuce in Wyoming.
Wyoming covers a very wide range of climates, so dates near you can be two weeks or more either side of these. Enter your ZIP code in the planting calendar for dates tuned to your town.
Wyoming: planting activity through the year
For fall and winter harvests (2)
Sowings counted back from Wyoming's first fall frost, so the crop matures before the cold - or, for garlic and similar, planted after it.
Harvesting in September
First harvests expected this month from crops sown or planted on time earlier in the season.
Planting dates for popular crops in Wyoming
Every crop has its own full-year dates for Wyoming: indoor start, transplant or direct sowing, and harvest.
Spring bulbs to plant in September in Wyoming
Tulips, daffodils, hyacinths and crocus are planted in fall, once the soil has cooled and before it freezes. The exact window depends on the state, so our bulb guide quotes what each extension service says.
After the first frost: September garden jobs in Wyoming
- The average first frost (September 15) has passed - pull frost-killed tender plants and compost the healthy ones; bin or burn anything that had blight or mildew.
- Plant garlic now (Sep 26 – Oct 13): single cloves, pointy end up, 2 inches deep and 6 inches apart, then mulch.
- Leave cold-hardy roots (carrots, parsnips, leeks) in the ground under a thick mulch and dig them as needed.
- Clean and oil tools, drain hoses, and note what worked this year while you still remember - it makes next year's plan far easier.
USDA zone chart for Wyoming
Wyoming spans USDA zones 3a, 3b, 4a, 4b, 5a, 6a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average.
Questions gardeners ask
What vegetables can I plant in Wyoming in September?
2 crops have a window in September: shallot, garlic. The tables above give the exact dates for each.
Is it too late to plant garlic in Wyoming in September?
No - plant in fall (after first frost) runs Sep 26 – Oct 13 in Wyoming.
Is it too late to plant tomatoes in Wyoming in September?
For this year, yes - the tomato windows in Wyoming have closed. The next step is to start seeds indoors from about March 25.
When is the first frost in Wyoming?
The statewide average first fall frost is around September 15 and the last spring frost around May 20. Wyoming covers a wide range of climates, so local dates can differ by two weeks or more - look yours up by ZIP code.
What can I harvest in Wyoming in September?
From plantings made on time: potato, sweet corn, bell pepper, cucumber, southern pea (cowpea), brussels sprouts, broccoli, cauliflower, cabbage, sunflower.
What to plant in September in other states
Dates are computed from Wyoming’s statewide average frost dates (from NOAA/NCEI climate normals) and each crop’s timing in our crop database. Your garden may be a week or two either side - for dates tuned to your ZIP code, use the planting calendar.