Maine · zones 3b–6a
When to plant kale in Maine.
Sow or transplant between Mar 31 to Apr 28 in a typical year, keyed to Maine's median last frost around May 8. A second, fall sowing fits Jul 7 to Aug 22. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Kale dates for a typical Maine season.
1 · Start indoors
Feb 17 to Mar 17
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Mar 31 to Apr 28
Keyed to the ~May 8 last frost. Sow 0.25" deep, 16" apart.
Fall round
Jul 7 to Aug 22
Counted back from the ~Oct 7 first frost.
Harvest
~45 days later
~2 lb per plant over ~16 weeks.
Maine spans more than one climate: Zone 5 is the most common zone, but the state runs 3b to 6a. 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.
In Maine: watch for
The pests that find kale here.
A middle-length season, about 152 frost-free days, means kale overlaps cabbage worms & loopers for a stretch each summer. Check plants every week or two and treat early.
Green caterpillars chewing ragged holes; green droppings.
Organic fix: Handpick, cover with netting, spray Bt.
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.
Seedlings wilt, yellow and stall for no reason; white maggots tunnel the roots.
Organic fix: Row cover before the flies are up, when yellow rocket blooms; rotate the bed.
Your season math: Maine gives kale about 152 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 Maine: questions
When should I plant kale in Maine?+
In a typical Maine year, sow kale or set out transplants between Mar 31 to Apr 28, keyed to the state's median last frost around May 8. There's also a fall window: Jul 7 to Aug 22. Your exact dates shift with your ZIP code and microclimate.
When do I start kale seeds indoors in Maine?+
Start seeds inside about 6 weeks before set-out: roughly Feb 17 to Mar 17 for a typical Maine season.
What USDA zone is Maine?+
Maine spans zones 3b–6a, mostly zone 5. 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.