Kale in Zone 4a & 4b

Brassica oleracea

When to plant kale in zone 4b

Zones 4a and 4b share the same average frost dates in our data, so this page covers both.

Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Kale tolerates either.

Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.

Kale is about as low-maintenance as vegetables get, and one of the few that improves with cold, a hard frost sweetens the leaves rather than ruining them. It can be started indoors or direct-seeded, and either way it tends to outlast most other greens into late fall.

How kale fits zone 4's season

Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Kale needs about 60 days from sowing to first harvest.

Good companions

• Onion: Onion scent is reputed to confuse cabbage moths that target kale. The research behind this is real but garlic-specific (field trials intercropping garlic with cabbage reduced diamondback moth damage) — onion hasn't been tested the same way, so treat the onion version as a reasonable extrapolation, not a directly measured result.

Where to buy kale seeds

• Botanical Interests
• True Leaf Market
• Burpee
• High Mowing Organic Seeds

See why we recommend these suppliers →

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See it growing

Search YouTube for "growing kale" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)

← Back to the full zone 4b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Kale in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.

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