Hawaii · zones 12a–12a
When to plant kale in Hawaii.
Sow or transplant between Nov 24 to Dec 22 in a typical year, keyed to Hawaii's median last frost around Jan 1. A second, fall sowing fits Sep 30 to Nov 15. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Kale dates for a typical Hawaii season.
1 · Start indoors
Oct 13 to Nov 10
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Nov 24 to Dec 22
Keyed to the ~Jan 1 last frost. Sow 0.25" deep, 16" apart.
Fall round
Sep 30 to Nov 15
Counted back from the ~Dec 31 first frost.
Harvest
~45 days later
~2 lb per plant over ~16 weeks.
Hawaii spans more than one climate: Zone 12 is the most common zone, but the state runs 12a to 12a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
Hawaii growing notes
Between the two brassicas sharing a pest list here, kale outlasts heat that stops broccoli cold, since a leaf never has to close into a head.
One planting round, even though both windows are open
A kale transplant here wants roughly 16 inches of room on each side and a planting depth of just a quarter inch, settling in fast enough for a first real harvest around 45 days out, then a substantial return for a leafy crop, about 2 pounds per plant across its life. Unlike lettuce on the same calendar, scheduled for over a dozen sowings, kale gets one planting round here, even though both a spring and a later window are marked open. Without a real seasonal swing making one window cooler than the other, there is little reason to treat them as separate plantings.
Because kale is not pulled whole the way a head crop is, one planting carries a household a long way. Harvest the larger outer leaves first, working from the bottom of the plant upward, and leave the small newest leaves at the crown alone; that crown keeps producing new growth for months as long as it is not stripped bare in a single pass. A plant cut this way, a little at a time, outlasts its own 45-day maturity mark by a wide margin.
Why kale shrugs off the same heat that ends broccoli's season
Kale and broccoli share the same five pests on this calendar, since both are the same basic plant, but the two do not share the same relationship with heat. Broccoli has to gather itself into one tight head to be worth harvesting, and that gathering leans on sustained cool weather; warmth instead leaves uneven heads and loose clusters of buds. Kale is never asked to do it. It simply grows leaves, one after another, and the warm stretch that spoils a head costs a kale plant nothing worse than tougher, sharper leaves.
So heat changes how to harvest here, not whether to plant. Taste a mid-sized raw leaf off a plant that has sat through a warm run: tough or sharp means start cutting leaves younger and cutting more often, since a small young leaf off a stressed plant still eats well and a big old one does not. No single structure is carrying the harvest, so a rough few weeks costs a few leaves and the crown keeps pushing new growth behind them.
The same five pests, read differently on a crop that gets cut instead of pulled
Cabbage worms and loopers feed on kale for as long as the plant stands, which on a crop harvested over months is a long stretch of exposure. Check the newest leaves near the crown first rather than the older leaves; both the caterpillars and the ragged holes they leave are easiest to spot there. Flea beetles hit hardest on young transplants, peppering leaves with a scatter of tiny round holes; a floating row cover for the first few weeks keeps them off while the plant is smallest. Aphids tuck into the base of leaf stems near the crown, low enough that a glance from standing height misses them; part the leaves there during a harvest pass.
Black rot shows as a V-shaped yellow wedge eating in from the leaf edge, with the veins inside it turned black or dark brown; cutting off and discarding any leaf showing that pattern doubles as harvest and disease control on a crop already cut leaf by leaf. Chinese rose beetle feeds only after dark and spends daylight buried at the plant's base, so a bed that looked whole at dusk shows fresh damage by morning with no beetle in sight. The pattern gives it away: tissue eaten out between the veins until a leaf reads like open lacework. A flashlight check after dark, beetles picked by hand into a jar of soapy water, works directly; a shallow pan of the same water under a dim bulb serves as a trap, kept dim, since bright light sends this beetle away.
In Hawaii: watch for
The pests that find kale here.
With about 364 frost-free days, kale spends longer in the ground here than in most of the country, which widens the window in which cabbage worms & loopers can find it. Scout weekly from midseason and act on the first signs.
Green caterpillars chewing ragged holes; green droppings.
Organic fix: Handpick, cover with netting, spray Bt.
Chinese rose beetle
Leaves chewed to lace between the veins, with no insect in sight by day.
Organic fix: Go out after dark with a jar of soapy water and pick them off, or hang a dim light over a soapy tray to trap them.
Gray-green clusters tucked into the leaf folds.
Organic fix: Blast with water, then insecticidal soap.
Tiny holes peppering the young leaves.
Organic fix: Row cover from day one; diatomaceous earth.
Black rot
Yellow V-shaped wedges cutting in from the leaf edge, veins blackening inside.
Organic fix: Pull infected plants, water at the base, keep brassicas out of that bed 3 years.
Your season math: Hawaii gives kale about 364 frost-free days, and it needs roughly 45 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting kale in Hawaii: questions
When should I plant kale in Hawaii?+
In a typical Hawaii year, sow kale or set out transplants between Nov 24 to Dec 22, keyed to the state's median last frost around Jan 1. There's also a fall window: Sep 30 to Nov 15. Your exact dates shift with your ZIP code and microclimate.
When do I start kale seeds indoors in Hawaii?+
Start seeds inside about 6 weeks before set-out: roughly Oct 13 to Nov 10 for a typical Hawaii season.
What USDA zone is Hawaii?+
Hawaii spans zones 12a–12a, mostly zone 12. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many kale plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.