Indiana · zones 5b–6b
When to plant lettuce in Indiana.
Sow between Mar 15 to Apr 29 in a typical year, keyed to Indiana's median last frost around Apr 22. A second, fall sowing fits Aug 3 to Oct 2. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Lettuce dates for a typical Indiana season.
Direct sow
Mar 15 to Apr 29
Keyed to the ~Apr 22 last frost. Sow 0.25" deep, 6" apart.
Fall round
Aug 3 to Oct 2
Counted back from the ~Oct 17 first frost.
Harvest
~45 days later
~0.4 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
Lettuce sown here for a fall cut almost never bolts before it's picked, while the same seed sown for spring is racing Indiana's early summer heat just to stay sweet.
Fall gives this crop room spring never does
Leaf lettuce needs only 45 days from a shallow, quarter-inch sowing to a head worth cutting, and at that pace Indiana's growing season has room for as many as 14 staggered sowings rather than one. A spring sowing is racing lengthening, warming days: once real heat settles in, the plant sends up a flower stalk and the leaves turn bitter and thin, done long before a gardener is ready to be finished with it. A fall sowing runs the opposite direction. Timed to mature as days shorten and cool instead of lengthen and warm, it has no reason to rush toward flower, so a head can sit finished in the row far longer without turning on the gardener.
The difference shows up on the tongue, not just the calendar. Taste a leaf from a spring planting once its center has started stretching upward toward a flower stalk, then taste a leaf from a fall planting cut well before any hard cold, and the spring leaf is sharper and thinner-tasting almost every time. Hot, dry soil in the middle of summer also makes this seed slower and less reliable to sprout, which is one more reason gardeners here tend to bunch most of their 14 possible sowings into spring and again from late summer into fall, leaving the hottest stretch of the calendar mostly empty.
Slugs and cutworms do their damage where you're not looking
Slugs and snails leave ragged holes and a silvery slime trail across the leaves, and the damage is easy to find; the animals doing it are not, since they feed at night and hide through the day. A board or a flat piece of cardboard left on the soil overnight works as a trap and a census at once: flip it in the morning and slugs looking for cover will have gathered underneath, giving an honest count of how bad the problem actually is before it shows up as missing leaves.
Cutworms work even lower, severing a seedling right at the soil line overnight so it's simply gone by morning or lying flat with a clean-cut stem, different from the ragged chewing slugs leave higher up on established leaves. Digging in the top inch of soil beside a felled seedling usually turns up a curled gray or brown grub. Pressing a barrier around each seedling stops a cutworm from reaching it at all: a cardboard tube cut in half and sunk an inch into the soil does the job as well as anything bought.
Aphids at the center, downy mildew from underneath
Aphids on lettuce gather on the undersides of the newest leaves near the center of the head rather than the older outer leaves, cupping and paling the tissue they feed on and leaving a faint sticky shine behind. Checking the outer leaves and calling a planting clean is the most common way to miss a colony that's already established; the center of the head, where the leaves are youngest and most tender, is where to look first.
Downy mildew shows as pale yellow blotches penned in by the leaf veins on top of a leaf, with a thin white fuzz on the underside that's easiest to catch after a cool, damp night. At 6 inches between plants, a row that has filled in leaves little room for air to move once heads size up, and still air over wet leaves is exactly what this disease wants. Watering in the morning instead of the evening gives the day's sun time to dry the foliage before a humid night sets in, which does more against downy mildew here than anything sprayed on after the blotches appear.
In Indiana: watch for
The pests that find lettuce here.
A middle-length season, about 178 frost-free days, means lettuce, leaf overlaps aphids for a stretch each summer. Check plants every week or two and treat early.
Clusters tucked into the heart of the head.
Organic fix: Rinse well; insecticidal soap on young plants.
Ragged holes and slime trails, worse after rain.
Organic fix: Iron-phosphate bait; a diatomaceous-earth ring; hand-pick at night.
Seedlings clipped off at the soil line overnight.
Organic fix: Collars around the stems; Bt or diatomaceous earth.
Pale yellow patches boxed in by the leaf veins, with white fuzz underneath.
Organic fix: Give plants room, let them dry between waterings, clear old leaves, and pick resistant varieties.
Your season math: Indiana gives lettuce about 178 frost-free days, and it needs roughly 45 days to a first harvest. That fits about 14 re-sown rounds across the season, so you can keep it coming instead of picking once.
Planting lettuce in Indiana: questions
When should I plant lettuce in Indiana?+
In a typical Indiana year, sow lettuce between Mar 15 to Apr 29, keyed to the state's median last frost around Apr 22. There's also a fall window: Aug 3 to Oct 2. 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 lettuce 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.