First and Last Frost Dates in Idaho
For the Boise area, NOAA’s 30-year climate data puts the last spring frost between April 23 and May 7, and the first fall frost between October 7 and…
Gardening in Idaho
Everything we have worked out for Idaho: 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 Boise, the last spring freeze runs April 23 to May 7 and the first fall freeze runs October 7 to October 21, USDA zones 3b-7b, 3,309 growing degree days in the year.
Garlic does well: 26.1 weeks below 40 °F, comfortably past the six it needs to form a proper head.
Elsewhere on the property in Idaho: 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.
When to Pick Tomatoes in Idaho, and Ripening the Rest
Pick tomatoes in Idaho as soon as frost is forecast, not after it hits. In the Boise area, the first fall frost typically lands between October 7 and…
When to Harvest Garlic in Idaho, and How to Cure It
Idaho garlic comes out of the ground the summer after fall planting, once the bottom leaves have browned while four or five up top stay green.
When to Pick Apples in Idaho, and How Long They Keep
Idaho apple harvest and storage depends on where in the state you’re growing.
Does Insulation Keep a Home in Idaho Cool?
Yes, but Idaho’s answer comes with an asterisk. The state straddles two IECC climate zones, both on the cold, dry side of the national map, and Boise…
Does a Wall in Idaho Need a Vapor Barrier?
Yes, most of Idaho falls under building code climate zones that require an interior vapor retarder on framed walls.
Heating With Pellets in Idaho: What a Winter Takes
Heating an Idaho home with pellets means budgeting for a long, genuinely cold season rather than a light one, buying two to three tons of fuel before the…
Trees, Shrubs and Perennials for Idaho: What Will Not Survive
Idaho’s growing conditions run from USDA zone 3b in the highest mountain valleys to zone 7b along the warmest stretches near the Snake River, a span wide…
How Much Insulation Does a Home in Idaho Need?
Idaho spans two IECC climate zones, 5B and 6B, split fairly evenly across its 44 counties.
When Can You Turn the Heat Off in Idaho?
September is the closest thing Idaho gets to a break from the thermostat: it’s the state’s quietest month, with roughly 199 combined heating and cooling…