Green beans (warm-season legume) is classed tender in the cited extension guidance. The timing rules below are relative to your local freeze dates — enter a location to turn them into calendar dates.
The rules this site applies
Method
Frost-relative window
Rule & reconciliation
Direct-sow outdoors
from the median last spring freeze to 2 weeks after
UGA: plant as soon as the danger of frost has passed; UNH: plant seed in garden after last frost; Purdue: tender — plant after the average last frost. Point rule given a 14-day span.
No start seeds indoors window: Beans resent transplanting and are direct-seeded in the cited guides.
Seed germination soil temperature: optimum 80°F (optimum range 60–85°F); minimum 60°F, maximum 95°F. Purdue HO-186-W Table 3. Cold soil below the minimum rots seed — a reason windows and soil readings both matter.
Variety assumption: Assumes bush snap beans (about 55–65 days from seed; Penn State lists 60).
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.