When to plant asparagus in Boise, Idaho
April 5 – April 19
Transplant outdoors · typical Boise yearClimate basis: NOAA station Boise 7 N, ID (USC00101017), 6 mi (9 km) from downtown Boise (ZCTA 83702 centroid), elevation 3885 ft, on the 1991–2020 climate normals. Plant asparagus crowns from approximately the dates above, anchored to the median last spring 32°F freeze (May 17). One year in ten still freezes after June 10.
The Boise year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to Jun 10
Every method, with its sources
Transplant outdoors
Apr 5 – Apr 19Purdue: hardy — plant crowns 4–6 weeks before the last spring frost. Anchored to the median last spring freeze (May 17). Purdue University Extension
Start seeds indoors
Not calculatedThe cited extension guides do not time an indoor seed-starting window for this crop.
Direct-sow outdoors
Not calculatedHome plantings start from 1-year crowns; seed-started asparagus adds a year and is not timed by the cited guide.
Fall planting
Not calculatedNo source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.
Variety assumption: A long-lived perennial; do not harvest the planting year, lightly the second year, fully from the third.
These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.
Crop rule sources (1)
- Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.