Indiana · zones 5b–6b
When to plant sweet corn in Indiana.
Sow between Apr 29 to Jul 27 in a typical year, keyed to Indiana's median last frost around Apr 22. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Sweet Corn dates for a typical Indiana season.
Direct sow
Apr 29 to Jul 27
Keyed to the ~Apr 22 last frost. Sow 1.5" deep, 12" apart.
Harvest
~75 days later
~1 lb per plant over ~1 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
Eleven staggered sowings turn sweet corn from a single hectic harvest into the steady summer supply that keeps roadside stands and county fair booths stocked for weeks.
A crop planted eleven times, not once
With only 75 days needed from seed to a ripe ear, sweet corn is short enough that Indiana's roughly 178-day season supports staggering it into as many as eleven separate sowings instead of committing the whole plot to a single planting date. That succession is what turns corn from one hectic harvest week into a steady supply through the heart of summer, the reason a roadside stand or a county fair booth can sell fresh ears for weeks running instead of one weekend. Each new sowing goes a foot apart in the row and about an inch and a half deep, deep enough to reach moisture that a hot summer surface loses fast, which matters more for a planting going into ground already baked hard by midsummer sun than for the first sowing, made while spring ground still holds moisture near the surface.
Treat every sowing as its own planting rather than an extension of the last one. A stand going in late in the sequence is walking into whatever earworm, borer, and rust pressure the earlier plantings have already built up in that same patch of ground over the summer, so the later sowings usually earn closer watching, not less, even though they're the easiest ones to let slide once the first harvest is already in the kitchen.
Three caterpillars, three different points of entry
Corn earworm, European corn borer, and fall armyworm are the three to know here, and telling them apart starts with where each one feeds, not what it looks like. Earworm works down from the tip of the ear, arriving by crawling in through the silk channel while it's still fresh and green, so pulling back the husk at the tip and checking the first inch or two of kernels is the direct test. European corn borer skips the silk entirely and tunnels straight into the stalk or the ear shank, leaving a small entry hole packed with coarse, sawdust-like frass, the kind of damage that can snap a stalk over in a summer storm well before harvest.
Fall armyworm targets young plants before an ear ever forms, feeding down in the whorl of unfurled leaves and leaving a ragged, torn pattern once those leaves unroll, almost like the plant was fed through a shredder in one spot. Checking the whorl on stands still a few weeks from tasseling catches armyworm at the stage where it does the most damage per caterpillar, since a worm feeding in the whorl of a young plant can wreck the growing point outright rather than just scarring an ear that's already filling out.
Rust rubs off on a finger, aphids leave a shine in the whorl
Common rust shows up as small, raised pustules scattered across both sides of a leaf, reddish-brown and powdery enough that rubbing a finger across an infected leaf picks up a rust-colored smear, the fastest field test for telling it apart from ordinary leaf wear. It tends to settle first on the older, lower leaves, the ones that stay wettest longest after a humid night, before working its way up the plant if the weather keeps favoring it.
Aphids on corn cluster in the whorl and around the developing tassel rather than spreading evenly across the plant, and a heavy colony leaves a sticky sheen on the leaves just below where they're feeding, visible as a faint shine even from a few feet off. Checking the whorl and the base of the tassel right as it starts to emerge catches a colony while it's still small enough that a strong spray of water from a hose knocks most of it loose.
In Indiana: watch for
The pests that find sweet corn here.
A middle-length season, about 178 frost-free days, means sweet corn overlaps corn earworm for a stretch each summer. Check plants every week or two and treat early.
Caterpillars feeding down in the tip of the ear.
Organic fix: A few drops of oil on the silk; Bt on the silks.
Broken tassels and frass-filled holes in the stalk.
Organic fix: Bt on young plants; cut and destroy stalks after harvest.
Clusters on the tassels and upper leaves.
Organic fix: Usually minor; insecticidal soap if heavy.
Fall armyworm
Ragged holes through the unfurling whorl leaves, with sawdust-like droppings down in the funnel.
Organic fix: Check whorls weekly before tassel; Bt or spinosad while the caterpillars are still small.
Cinnamon-brown powdery pustules breaking out on BOTH sides of the same leaf, lower leaves first, darkening as they age.
Organic fix: Water at the ground rather than overhead, and choose resistant varieties next season; sprays are rarely worth it.
Your season math: Indiana gives sweet corn about 178 frost-free days, and it needs roughly 75 days to a first harvest. That fits about 11 re-sown rounds across the season, so you can keep it coming instead of picking once.
Planting sweet corn in Indiana: questions
When should I plant sweet corn in Indiana?+
In a typical Indiana year, sow sweet corn between Apr 29 to Jul 27, keyed to the state's median last frost around Apr 22. Your exact dates shift with your ZIP code and microclimate.
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 sweet corn 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.