The Wyoming Lawn Care Calendar, Month by Month
A season-by-season Wyoming lawn calendar built on Cheyenne’s NOAA frost dates, the cool-season grasses that survive here, and how elevation shifts the timing.
Gardening in Wyoming
Everything we have worked out for Wyoming: what to plant and when, which varieties finish in time, the pests that actually turn up here, and the jobs that pay off month by month. We also cover the rest of the property, from lawns and soil to home care and energy, because a garden rarely stops at the vegetable bed.
The numbers first, because everything else follows from them. Measured at the weather station in Cheyenne, the last spring freeze runs May 7 to May 18 and the first fall freeze runs September 24 to October 5, USDA zones 3a-6a, 2,552 growing degree days in the year.
Garlic does well: 30.4 weeks below 40 °F, comfortably past the six it needs to form a proper head.
Elsewhere on the property in Wyoming: the pests that turn up here.
Figures from NOAA's 1991-2020 climate normals. A state is not one climate: elevation, a large lake or the coast can move these dates by two weeks either way, so check your own county with the extension service before you spend money.
Mexican bean beetle in Wyoming: When It Shows Up and What Stops It
Mexican bean beetle shows up in Wyoming gardens mostly in July and August, and even then it’s rarely the widespread menace it is in states like Nebraska…
Flea beetles in Wyoming: When It Shows Up and What Stops It
Flea beetles start chewing through Wyoming gardens as soon as soil temperatures climb into the mid-50s, which typically lands somewhere between mid-May…
Colorado potato beetle in Wyoming: When It Shows Up and What Stops It
Colorado potato beetles typically appear in Wyoming gardens and potato fields between late May and mid-June, once soil temperatures climb past the…
Grasshoppers in Wyoming: When It Shows Up and What Stops It
Grasshoppers turn up across Wyoming from late May through September, with numbers peaking in July and August when nymphs finish molting into flying adults.
Tomato hornworm in Wyoming: When It Shows Up and What Stops It
Tomato hornworms show up in Wyoming later than almost anywhere else in the country, typically from mid-July through early September, and the state’s…
Aphids in Wyoming: When It Shows Up and What Stops It
Aphids show up in Wyoming gardens and shelterbelts as soon as tender new growth appears, usually mid-to-late May in the warmer valleys around Cheyenne…
Blister beetles in Wyoming: When It Shows Up and What Stops It
Blister beetles show up in Wyoming from late June through August, typically after a run of warm, dry weather following alfalfa’s first cutting.
Root maggots in Wyoming: When It Shows Up and What Stops It
Root maggots start hitting Wyoming gardens as soon as soil temperatures climb into the mid-40s Fahrenheit, usually late April in Cheyenne and Torrington…
Cutworms in Wyoming: When It Shows Up and What Stops It
Cutworms show up twice a year in Wyoming: a late-summer to fall hatch that feeds until frost, and a second feeding push in early spring once the ground…