Indiana · zones 5b–6b
When to plant broccoli in Indiana.
Sow or transplant between Mar 1 to Mar 29 in a typical year, keyed to Indiana's median last frost around Apr 22. A second, fall sowing fits Jul 3 to Aug 12. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Broccoli dates for a typical Indiana season.
1 · Start indoors
Jan 18 to Feb 15
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Mar 1 to Mar 29
Keyed to the ~Apr 22 last frost. Sow 0.5" deep, 18" apart.
Fall round
Jul 3 to Aug 12
Counted back from the ~Oct 17 first frost.
Harvest
~60 days later
~1.2 lb per plant over ~3 weeks.
Indiana spans more than one climate: Zone 6 is the most common zone, but the state runs 5b to 6b. 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.
Indiana growing notes
Broccoli set for an Indiana spring races to finish one tight head before summer heat arrives to loosen it, which is why the fall planting, timed to finish as the weather cools, is the one that reliably comes together.
One head, one shot, and why fall gives it room
Broccoli transplants go in 18 inches apart and need about 60 days to size up a head worth cutting, and because this crop is grown as one planting per window, not staggered sowings, the whole harvest rides on that one head forming correctly. Spring's problem is timing: the transplant is racing to finish its head before real heat arrives, and if a hot stretch lands right as the buds are tightening, the head can loosen and start showing yellow between the florets, the plant shifting from building a head to trying to flower. Once that shift starts, the head won't tighten back up, no matter how much longer it sits in the ground.
A fall planting removes that race entirely. Transplants set out in mid to late summer size up their head as the weather cools rather than heats, so the plant has no reason to rush toward flower, and a properly finished head holds in the field longer before it has to be cut. Belstar and Waltham 29 are common variety choices for that fall slot here, both known more for holding up through a cooling, sometimes frosty finish than for raw speed.
What gets into the head is the real problem, not what's on the leaves
Cabbage worms and loopers do plenty of damage to open leaves, but the costly damage on this crop happens when one works down between the tight clusters of buds that make up the head itself, a spot no spray reaches and easy to miss since the caterpillar's green blends into the buds around it. A head close to cutting is worth checking before it goes anywhere near the kitchen: soak it cut-side down in a bowl of salted water for several minutes, and anything hidden between the florets loses its grip and drifts loose into the water, worth doing every time on a crop where the harvest is one dense head, not loose leaves.
Aphids get into those same tight spaces, nesting down between the flower buds where they're just as hard to see or rinse clean under a tap. A head carrying a heavy colony often shows a faint grayish cast low between the buds if you look closely before cutting it. The same salted-water soak that flushes out hidden caterpillars usually knocks these loose too, one more reason that soak is worth the extra minutes on this crop.
Flea beetles, black rot, and a maggot: higher stakes on a one-shot head
Flea beetles do their worst in the first couple of weeks after a broccoli transplant goes into open ground, stippling young leaves with small round holes. Most crops can shrug that off, but broccoli spends those same weeks building the leaf area that will later fund a head that gets only one attempt to form, so heavy early feeding can slow the whole plant down somewhere inside its 60-day window. A cover over the bed for that early stretch keeps the beetles off while the plant has the least leaf to spare.
Black rot's yellow, vein-blackening lesions and cabbage root maggot's underground feeding both cost a leaf-picked crop a leaf or two and little else. On broccoli, with a single head from a single planting, either problem reaching the main stem or stunting the plant before the head forms costs the entire harvest, not a portion of it. Catching either early matters more here than on a crop that can just shed a damaged leaf and keep going: cut open a blackened vein at the first yellow patch, or dig at the base of a wilting transplant to check the roots for maggots before deciding it's just thirsty.
In Indiana: watch for
The pests that find broccoli here.
A middle-length season, about 178 frost-free days, means broccoli 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: Indiana gives broccoli about 178 frost-free days, and it needs roughly 60 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting broccoli in Indiana: questions
When should I plant broccoli in Indiana?+
In a typical Indiana year, sow broccoli or set out transplants between Mar 1 to Mar 29, keyed to the state's median last frost around Apr 22. There's also a fall window: Jul 3 to Aug 12. Your exact dates shift with your ZIP code and microclimate.
When do I start broccoli seeds indoors in Indiana?+
Start seeds inside about 6 weeks before set-out: roughly Jan 18 to Feb 15 for a typical Indiana season.
What USDA zone is Indiana?+
Indiana spans zones 5b–6b, mostly zone 6. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many broccoli 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.