How to Grow Kale

A cool-season crop that laughs at frost

Kale is happiest in cool weather and, unlike heat-loving crops, is timed for spring and fall. Utah State Extension sets spring transplants out 4 to 5 weeks before the last frost-free date, and for fall picks early-maturing varieties planted 50 to 75 days before the target harvest.

Its headline trait is cold hardiness. Young kale plants are not seriously damaged by temperatures down to 25°F, and mature plants are extremely hardy, withstanding very cold temperatures — which is why kale keeps producing long after tender greens are done for the year.

Space plants about 12 inches apart in rows 2 feet apart in full sun and fertile soil. Recommended varieties like Red Russian mature in about 50 days and curly types like Starbor and Scarlet in about 55.

Frost makes it sweeter

Cold weather does not just fail to hurt kale — it improves it. Utah State notes frosts help improve the flavor of the fall-planted crop, as the plant converts starches to sugars in response to cold, taking the edge off the leaves.

That flips the usual harvest logic: instead of racing to beat frost, you wait for it. The fall kale crop is deliberately left in the garden through the first freezes, and in many regions it keeps going into winter.

Kale also tastes best when it grows fast, either maturing before summer heat or through the cool of fall. Slow, heat-stressed kale in midsummer turns tough and bitter, so the shoulder seasons win on flavor twice over.

Bottom-up, cut-and-come-again harvest

Kale is a cut-and-come-again crop. Strip the older, larger leaves from the bottom of the plant first, taking only a few leaves per plant at a time and leaving the central growing point and the young upper leaves intact so the plant keeps producing.

Done this way, one planting yields for months — the plant grows taller on a bare lower stem while continually pushing new leaves from the top. Pick leaves while they are still tender rather than letting them get oversized and tough.

For fresh use, harvested kale keeps about 2 to 3 weeks at 32°F and 95% relative humidity. For per-point planting dates, spacing, watering, and fertilizer figures, and for holes-in-the-leaves pest issues, see the kale calculators and troubleshooting pages.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• Utah State University Extension — How to Grow Kale in Your Garden — Set spring transplants 4-5 weeks before the last frost-free date; for fall, plant early-maturing cultivars 50-75 days before anticipated maturity; space 12 inches between plants in rows 2 feet apart; recommended varieties mature in about 50-55 days; young plants are not seriously damaged down to 25°F and mature plants are extremely hardy; frosts help improve the flavor of the fall-planted crop; older leaves are stripped off first, allowing the young leaves to continue to grow; store 2-3 weeks at 32°F and 95% relative humidity.
• University of Minnesota Extension — Growing collards and kale in home gardens — Kale is cold tolerant and continues to grow and produce new leaves well beyond the first fall frosts; harvest by breaking off individual leaves starting from the bottom of the plant and moving up over time, taking only a few leaves per plant so it can recover; flavor is enhanced after frost.

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