When Sweet Corn Is Ready in Colorado, and How Fast It Fades
Sweet corn in Colorado is ready about 60 to 90 days after planting, and planting waits on the soil, not the calendar.
Colorado
Home and garden guidance specific to Colorado: climate, seasons, local rules and rebates.
Gardening in Colorado
Everything we have worked out for Colorado: 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 Denver, the last spring freeze runs May 1 to May 11 and the first fall freeze runs September 30 to October 12, USDA zones 3b-7b, 3,401 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 Colorado: 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.
Heat Pump or Gas Furnace in Colorado: Which Costs Less to Run?
In Colorado, a natural gas furnace costs less to run than an air-source heat pump at average residential prices.
When to Plant Grass Seed in Colorado
In the Denver area, cool-season grass seed goes down in late summer, and the last sowing falls about 45 days before the first fall freeze.
How High to Mow a Lawn in Colorado
Mow tall fescue at 3 to 3.5 inches, Kentucky bluegrass at 2 to 3, perennial ryegrass at 1.5 to 2.5, and zoysiagrass or bermudagrass at 1 to 2.
When to Dethatch a Lawn in Colorado
For most Colorado lawns, the answer is never. Dethatching only pays off when the thatch layer measures more than 0.75 inch, and even then the timing…
When to Aerate a Lawn in Colorado
For a cool-season lawn near Denver, aerate in fall while the grass is still growing, and finish before the first freeze.
How Late Can You Plant Trees and Shrubs in Fall in Colorado?
Six weeks before the first fall frost is the safe target. In Denver, where frost arrives between September 30 and October 12 (NOAA’s 1991-2020 normals)…
When to Mulch Strawberries and Perennials for Winter in Colorado
Wait until the ground has started to freeze, then mulch. In Denver, the first fall frost lands between September 30 and October 12 (NOAA NCEI 1991-2020…
When to Dig Up Dahlias, Cannas and Gladiolus in Colorado
In Colorado, dahlias, cannas and gladiolus come up every fall. Denver’s coldest month averages a daily low of 18.4°F (NOAA NCEI 1991-2020 normals), too…
When to Winterize Sprinklers and Outdoor Faucets in Colorado
Shut down irrigation and drain outdoor faucets before the first hard freeze, not after the first light one.