Kalettes in Zone 4a & 4b
Brassica oleracea
Yes, Kalettes grow in zones 4a and 4b. Start seeds indoors Apr 3–Apr 10 and plant out May 1–May 8.
When to plant Kalettes in zone 4b
Zones 4a and 4b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. It needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Apr 3–Apr 10 |
|---|---|
| Direct sow / transplant outside | May 1–May 8 |
| Estimated harvest | Aug 9–Aug 16 (~100 days after transplanting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-3 ft.
Plant alongside it in zone 4b
These go outside within two weeks of Kalettes in zone 4b, so one planting day can cover them.
- OnionApr 24–May 1
- CarrotApr 24–May 1
- CabbageMay 1–May 8
- LettuceMay 1–May 8
- BroccoliMay 1–May 8
- Flower SproutsMay 1–May 8
Kalettes is a trademarked cross between kale and Brussels sprouts, grown for small, frilly-leaved florets that look nothing like the tight round sprouts of its Brussels parent, with a milder, sweeter flavor to match.
How Kalettes fit zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Kalettes need about 100 days from transplant to first harvest.
Kalettes planting windows in every zone
Zone 4b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 2a & 2b | Apr 8–Apr 15 | May 6–May 13 | Aug 14–Aug 21 |
| 3a & 3b | Apr 18–Apr 25 | May 16–May 23 | Aug 24–Aug 31 |
| 4a & 4b (your zone) | Apr 3–Apr 10 | May 1–May 8 | Aug 9–Aug 16 |
| 5a & 5b | Mar 29–Apr 5 | Apr 26–May 3 | Aug 4–Aug 11 |
| 6a & 6b | Mar 14–Mar 21 | Apr 11–Apr 18 | Jul 20–Jul 27 |
| 7a & 7b | Feb 27–Mar 6 | Mar 27–Apr 3 | Jul 5–Jul 12 |
| 8a & 8b | Feb 11–Feb 18 | Mar 11–Mar 18 | Jun 19–Jun 26 |
| 9a & 9b | Jan 4–Jan 11 | Feb 1–Feb 8 | May 12–May 19 |
| 10a & 10b | Dec 19–Dec 26 | Jan 16–Jan 23 | Apr 26–May 3 |
| 11a & 11b | Nov 20–Nov 27 | Dec 18–Dec 25 | Mar 28–Apr 4 |
Harvest dates are about 100 days after the sow or plant-out date, not after starting seeds indoors.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
- Radish: Radish (including the daikon form) is a documented trap crop for flea beetles, which prefer its mustard oils over other brassicas and can be sacrificed or pulled once infested: the same research cited on the radish page.
Where to buy kalette seeds
None of the seed suppliers we list carries kalette seeds right now. A local garden center or a specialty seed house is the place to look.
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing Kalettes" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Plan your beds in the Garden Designer →
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Growing Kalettes in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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