Plant Beans (bush) in Zone 9b

Zone 9b averages 298 frost-free days, running from a last spring frost around February 15 to a first fall frost around December 10. Beans (bush) needs roughly 55 days from planting out to first harvest, so it uses about 18 percent of that window. Beans (bush) is a tender crop, which is what decides where in the window it belongs.

Beans (bush) resents transplanting and hates cold soil, so direct sow around Feb 22, after the Zone 9b last frost has passed and the soil has warmed. At 55 days to harvest, a 298-day Zone 9b season has room for about 4 sowings, so stagger them rather than planting everything at once.

Yes. Sow beans (bush) by September 18 in Zone 9b. That is 83 days before the average first frost, which covers the 55 days to maturity plus about two weeks for the slower growth that comes with shortening days, plus a two week margin because frost kills beans (bush) outright.

Bush beans mature fast enough for a second sowing almost anywhere with a frost-free window into October.