Plant Kale in Zone 9a

Zone 9a averages 274 frost-free days, running from a last spring frost around March 1 to a first fall frost around November 30. Kale needs roughly 60 days from planting out to first harvest, so it uses about 22 percent of that window. Kale is a hardy crop, which is what decides where in the window it belongs.

Because kale needs a head start, sow seed indoors around Jan 18, about 6 weeks ahead of the Zone 9a last frost. Transplants go out around Feb 15. Starting earlier than that in Zone 9a usually backfires: plants outgrow their cells and stall when they finally hit cold soil. At 60 days to harvest, a 274-day Zone 9a season has room for about 3 sowings, so stagger them rather than planting everything at once.

Yes. Sow kale by October 15 in Zone 9a. That is 46 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, minus the roughly 28 days kale keeps going once light frost arrives.

Kale is usually the last thing standing in the garden. Frost converts its starch to sugar, so the flavour improves after the first freeze.