Plant Cucumbers in Zone 8b

Zone 8b averages 245 frost-free days, running from a last spring frost around March 15 to a first fall frost around November 15. Cucumbers needs roughly 60 days from planting out to first harvest, so it uses about 24 percent of that window. Cucumbers is a tender crop, which is what decides where in the window it belongs.

Because cucumbers needs a head start, sow seed indoors around Feb 22, about 3 weeks ahead of the Zone 8b last frost. Transplants go out around Mar 29. Starting earlier than that in Zone 8b usually backfires: plants outgrow their cells and stall when they finally hit cold soil. At 60 days to harvest, a 245-day Zone 8b season has room for about 3 sowings, so stagger them rather than planting everything at once.

Yes. Sow cucumbers by August 19 in Zone 8b. That is 88 days before the average first frost, which covers the 60 days to maturity plus about two weeks for the slower growth that comes with shortening days, plus a two week margin because frost kills cucumbers outright.

A second sowing in midsummer usually dodges the worst of the cucumber beetle and powdery mildew pressure that kills the spring planting.