Trees, Shrubs and Perennials for Colorado: What Will Not Survive
Colorado’s growing conditions run from the high plains around Denver to alpine valleys where summer barely gets going.
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.
How Much Insulation Does a Home in Colorado Need?
Colorado doesn’t have a single insulation number, because it doesn’t have a single climate.
When Can You Turn the Heat Off in Colorado?
In Colorado, the quietest point in the heating-and-cooling cycle falls in June, but “quiet” needs a caveat: the degree-day count that month is far from…
Will Sweet Corn Ripen in Colorado?
Yes, in most of Colorado’s populated valleys and plains, sweet corn can ripen before the first fall frost, but the calendar math is tighter than…
When to Sow Sweet Corn in Colorado
In most of Colorado, sweet corn goes into the ground once soil has warmed past 60 F, which lands later than the last spring frost (May 1 to May 11 on the…
Will Colorado Soil Hold an Asparagus Bed for Fifteen Years?
Colorado’s representative soil, the Seitz series, is classed as well drained — which is the only soil condition asparagus actually asks for.
When to Plant Asparagus Crowns in Colorado
In Colorado, asparagus crowns go into the ground in early spring, timed to the region’s mean last spring frost window of around May 1 to May 11.
Growing Sweet Corn in Colorado: Will It Ripen?
Yes, sweet corn can ripen in most of Colorado’s populated valleys and plains, but the calendar is tighter than the frost dates alone suggest.
Growing Asparagus in Colorado: Fifteen Years in One Spot
Colorado can grow asparagus, but the bed you dig this spring is the bed your household will still be cutting from in a decade and a half.
When to Sow Autumn Spinach in Colorado
In Colorado, the safest bet is to sow autumn spinach seed sometime between mid-July and late August, counting backward from the first fall frost, but…