Indiana · zones 5b–6b
When to plant sweet potatoes in Indiana.
Sow or transplant between May 29 to Jun 15 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 Potatoes dates for a typical Indiana season.
1 · Start indoors
Apr 17 to May 4
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
May 29 to Jun 15
Keyed to the ~Apr 22 last frost. Sow 3" deep, 14" apart.
Harvest
~110 days later
~2.5 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
Sweet potato needs 110 warm days inside Indiana's 178-day season, a tighter margin than most vegetables grown here get, and despite the name it isn't kin to the potato at all.
A morning glory relative, not a nightshade
Sweet potato goes in here as transplants called slips, spaced about 14 inches apart with the buried stem set roughly 3 inches deep, and needs about 110 days of real warmth to bulk up the roughly 2.5 pounds of roots a plant typically produces. Beyond the name, it shares little with the true potato: sweet potato belongs to the morning glory family, not the nightshade family that potatoes, tomatoes, and peppers belong to. What a grower learns to watch for in a potato patch is not what troubles this one, and the habits worth keeping are aimed below the soil, not at the leaves.
What sweet potato deals with instead is its own trio of regulars: wireworms and white grubs, aphids, and black rot. The one that matters most here, black rot, is not a potato problem at all, and treating every sweet potato issue as though it were a potato issue, reaching for a fix aimed at blight or at a striped beetle, wastes effort on organisms that were never the actual threat. Sweetpotato weevil is worth knowing too, covered below, though it isn't established in Indiana yet.
Chasing warmth on a tight calendar
Indiana's frost-free stretch runs about 178 days, and a crop needing 110 of them leaves a little over two months of slack on both ends combined, not much room to spare if spring starts slow and cool. The plant doesn't just want frost-free air, it wants genuinely warm soil before it puts on real growth, and slips set into ground still cool from a late spring tend to sit and sulk rather than root out and run. Many Indiana growers push soil temperature up early with a sheet of black plastic laid over the bed before setting slips, warming the top few inches enough that transplants take off right away instead of losing part of their short margin.
That same plastic keeps paying off through summer by holding soil warmth overnight and blocking weeds from competing with a crop that spends its first several weeks building vine before it really starts bulking roots. A grower unsure whether a bed is warm enough to plant can press a hand flat against the soil a couple of inches down in the morning; ground that still feels cool to the touch that late in the day is asking a slip to root into conditions it isn't ready for.
A weevil best kept out, and two problems that start below ground
Sweetpotato weevil deserves the most caution of anything covered here: it's the most serious pest this crop can have anywhere it takes hold, and it typically arrives on infected slips rather than developing on its own in clean ground. The defense happens entirely before planting: buying slips only from a certified source and checking the base of each one for tiny holes or notches in the stem keeps an infestation from ever starting. A slip that looks chewed or scarred at the soil line is worth discarding rather than planting, since a weevil problem established underground is far harder to deal with than one refused at the door.
Wireworms and white grubs live in the soil and do their damage out of sight, tunneling into roots and leaving holes that show up only at harvest, and both are common in a bed recently converted from lawn or grass. A bait test flags them before a whole bed goes in: bury a chunk of raw potato or carrot a few inches deep, mark the spot with a stick, and dig it up after about a week. Finding several grubs or wireworms in that piece means the bed would benefit from another season of cultivation first. Aphids cluster on new growth same as elsewhere, and black rot shows up as firm, dark, sunken lesions on the roots, often carried in on infected slips.
In Indiana: watch for
The pests that find sweet potatoes here.
A middle-length season, about 178 frost-free days, means sweet potato overlaps wireworms & white grubs for a stretch each summer. Check plants every week or two and treat early.
Wireworms & white grubs
Shallow holes and grooves chewed into the roots, found only at digging time.
Organic fix: Avoid planting into ground that was in sod last year; rotate away from grassy beds.
Clusters on the tender growing tips of new vines.
Organic fix: Hose them off in the morning, or use insecticidal soap.
Black rot
Dry, firm dark patches on the roots, usually found at harvest or in storage, with a sweet fruity smell.
Organic fix: Start from clean slips cut well above the soil line, never save roots from a bad crop, and rotate 3 years.
Your season math: Indiana gives sweet potatoes about 178 frost-free days, and it needs roughly 110 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting sweet potatoes in Indiana: questions
When should I plant sweet potatoes in Indiana?+
In a typical Indiana year, sow sweet potatoes or set out transplants between May 29 to Jun 15, keyed to the state's median last frost around Apr 22. Your exact dates shift with your ZIP code and microclimate.
When do I start sweet potatoes seeds indoors in Indiana?+
Start seeds inside about 6 weeks before set-out: roughly Apr 17 to May 4 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 sweet potatoes 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.