Growing Kale: A Complete Profile
By Growing Home Greens Team · July 18, 2026
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.
Starting it indoors or direct in cool soil
Start it indoors six weeks before your last frost, or direct-seed as early as three weeks before. Kale tolerates cool soil well. At 60 days to maturity and one plant per square foot, it takes more room than a dense green like spinach but rewards it with a much longer harvest window; you can keep picking outer leaves for months rather than harvesting once.
Flea beetles, and the tomato it doesn’t get along with
Small holes riddling the leaves are usually flea beetles or cabbage worms. Row cover early in the season heads off most of the damage before it starts. Kale planted too close to tomatoes can stunt their growth, so keep some distance between the two even though neither is a food-safety issue, just a competition one.
Keep it away from the tomatoes
Onion is a documented companion, its scent is thought to confuse the cabbage moths that target kale. See the full companion guide for kale. Keep it away from tomatoes in your bed layout in the Garden Designer, since kale can stunt tomato growth when planted too close.
Companion planting guide for Kale · Find your planting dates
Typically viable in USDA zones 2-10. Not sure your zone? Look it up by ZIP code.
Mature height: 1-2 ft
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
When to plant kale, by zone
Every zone kale grows in. Pick your zone in the header and it will be highlighted here. Each zone links to its full page.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 2a & 2b | Apr 8–Apr 15 | Apr 29–May 6 | Jun 28–Jul 5 |
| 3a & 3b | Apr 18–Apr 25 | May 9–May 16 | Jul 8–Jul 15 |
| 4a & 4bSpring window | Apr 3–Apr 10 | Apr 24–May 1 | Jun 23–Jun 30 |
| Fall window | Not usually | Jul 8–Jul 22 | Sep 6–Sep 20 |
| 5a & 5bSpring window | Mar 29–Apr 5 | Apr 19–Apr 26 | Jun 18–Jun 25 |
| Fall window | Not usually | Jul 23–Aug 6 | Sep 21–Oct 5 |
| 6a & 6bSpring window | Mar 14–Mar 21 | Apr 4–Apr 11 | Jun 3–Jun 10 |
| Fall window | Not usually | Aug 2–Aug 16 | Oct 1–Oct 15 |
| 7a & 7bSpring window | Feb 27–Mar 6 | Mar 20–Mar 27 | May 19–May 26 |
| Fall window | Not usually | Aug 12–Aug 26 | Oct 11–Oct 25 |
| 8a & 8bSpring window | Feb 11–Feb 18 | Mar 4–Mar 11 | May 3–May 10 |
| Fall window | Not usually | Aug 28–Sep 11 | Oct 27–Nov 10 |
| 9a & 9bSpring window | Jan 4–Jan 11 | Jan 25–Feb 1 | Mar 26–Apr 2 |
| Fall window | Not usually | Sep 22–Oct 6 | Nov 21–Dec 5 |
| 10a & 10bFall window | Aug–Dec | Sep–Jan | ~60 days after transplanting |
Harvest dates are about 60 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.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Kale plants fit per square foot?
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Soil & water: pH 6.2-6.5. Needs well-drained soil. Amend with lime if soil pH falls below 6.2.
Good companions for kale
- 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.
Full companion guide, including what to keep away from kale →
Varieties worth considering
- Winterbor (F1): Described by the seed company as showing good cold hardiness and excellent yield, and generally regarded as one of the hardiest curly kale types for extending harvest into cold weather. (source)
- Red Russian: Cornell's Vegetable Varieties for Gardeners database has it as the most-reviewed kale in their system at 33 reviews and a 4.4-star rating, with oak-shaped, gray-green leaves and deep-purple veins that are noticeably more tender than curly types like Winterbor. (source) Buy seeds: Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds
- Toscano (Lacinato/Dinosaur kale): Cornell's database rates it 4.4 stars with dark-green, blistered, strap-shaped leaves noted as resistant to both heat and cold. The type most often called for in Tuscan soups, and a different texture entirely from the curly types. (source)
Why each variety is listed comes from the source shown next to it. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement. The buy links are separate from those sources: they go to seed suppliers that sell that exact variety, and we may earn a commission on some of them.
Where to buy kale seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's kale seeds)
The varieties we recommend above each have their own buy links, for the suppliers that sell that exact variety.
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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)
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Growing Kale: A cold-hardy green that tastes better after a frost, one of the easiest crops to keep going late.
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