When to plant lima bean in Boise, Idaho
May 17 – May 31
Direct-sow 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. Direct-sow lima bean 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
Direct-sow outdoors
May 17 – May 31Illinois Extension's Hort Answers entry for Phaseolus vulgaris and P. lunatus says beans should be planted after all danger of frost is past, and Utah State's legume planting guide places the warm-season legumes — which it lists as snap or dry beans and lima bean — around the frost-free date; both point to the last-frost date itself, so the point rule opens the window at the anchor and runs the standard 14 days. Illinois' allowance for planting a week to 10 days early in warm soil was rejected as the earlier-starting, less frost-conservative reading. Anchored to the median last spring freeze (May 17). Utah State University Extension
Start seeds indoors
Not calculatedThe cited extension guides do not time an indoor seed-starting window for this crop.
Transplant outdoors
Not calculatedThe cited extension guides do not time an outdoor transplanting window for this crop.
Fall planting
Not calculatedNo source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.
Variety assumption: Assumes bush or pole lima sown directly in place; Maryland Extension notes limas need soil at 65°F for five days to germinate well, so gardeners in a cold spring should plant toward the later end of the window rather than at its opening.
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)
- Utah State University Extension: Planting and Spacing — Legumes (Vegetable Guide) (accessed 2026-07-25)"Plant the cool-season legumes several weeks before and the warm-season legumes around the frost-free date for the location."