Michigan · zones 4b–6b
When to plant potatoes in Michigan.
Sow between Mar 28 to Apr 30 in a typical year, keyed to Michigan's median last frost around May 5. A second, fall sowing fits Jun 20 to Jul 3. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Potatoes dates for a typical Michigan season.
Direct sow
Mar 28 to Apr 30
Keyed to the ~May 5 last frost. Sow 4" deep, 12" apart.
Fall round
Jun 20 to Jul 3
Counted back from the ~Oct 8 first frost.
Harvest
~90 days later
~3 lb per plant over ~1 weeks.
Michigan spans more than one climate: Zone 6 is the most common zone, but the state runs 4b 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.
Michigan growing notes
Michigan grows chip potatoes. Your backyard can borrow the playbook.
Sand country and the scab-suppression trick chip growers use
Central Michigan's potato belt, the sandy ground running through Montcalm County, the top potato-producing county in Michigan, the nation's leading chip-potato state, grows on soil that is naturally acidic and drains fast, and both traits matter more than most gardeners realize. Sandy, acidic ground at or below pH 5.2 reliably suppresses common scab, the disease that pits potato skins with rough brown patches; control gets shaky as pH climbs past that mark, and soil above pH 6.0 lets scab run freely. If your bed needed lime for a previous crop, plant potatoes somewhere else this year instead of trying to fix it back down.
Snowden and Atlantic are the chip-stock varieties that built that industry, both bred for the dense, low-sugar flesh that fries evenly, and both grow just as well in a home bed. Hill soil up around the stems as they grow, adding 2 to 3 inches each time the plant gains that much height, until the hill stands 6 to 8 inches tall; tubers that form above the covered soil turn green and bitter from sun exposure, and hilling is the only real defense against it.
Colorado potato beetle times its emergence to soil warmth
Colorado potato beetle overwinters as an adult buried a few inches down in the soil right where last year's potatoes grew, and it waits for the ground to warm before climbing out, which near Lake Michigan's cooling shoreline effect runs later than it does 30 miles inland. Check the undersides of the first leaves as soon as plants emerge; the adult is the unmistakable half-inch beetle with black and cream stripes running down its back, and a female lays clusters of 20 or more bright orange eggs on a single leaf.
Crushing those egg clusters by hand during the first 2 weeks after emergence removes more beetles per minute than any other single action, because each cluster you miss becomes a dozen hungry larvae within a week. Rotating the potato bed at least 20 feet from last year's spot forces the newly emerged adults to walk further to find food, and a surprising number never make it, since they are slow, ground-bound crawlers rather than strong fliers this early in the season.
Late blight loves a humid Great Lakes August
Late blight, the disease behind the historic Irish potato famine, is still very much active in the Great Lakes region and shows up as water-soaked, blackish-brown blotches on leaves that can spread across a whole plant within days during a cool, humid stretch, the kind of weather that lake-effect humidity delivers regularly by late summer. Unlike most garden diseases, this one can move field to field on wind-blown spores, so check plants after any multi-day damp period rather than waiting for a weekly routine to come around.
There is no saving a plant once blight takes hold, so the response is removal: pull and bag infected plants immediately rather than composting them, since home compost piles rarely get hot enough to kill the spores. Keep foliage dry by watering at the soil line, and once tops die back naturally near season's end, wait a full 2 weeks before digging so the skins toughen enough to store through winter instead of bruising and rotting in storage soon after.
In Michigan: watch for
The pests that find potatoes here.
A middle-length season, about 156 frost-free days, means potato overlaps colorado potato beetle for a stretch each summer. Check plants every week or two and treat early.
Striped beetles and orange grubs eating the leaves.
Organic fix: Handpick adults, crush the orange egg clusters, dust with diatomaceous earth.
Dark greasy blotches after cool, wet spells.
Organic fix: Pull infected plants fast, keep leaves dry, use neem as a preventive.
Common scab
Rough, corky patches on the skin, raised on some tubers and sunk into pits on others.
Organic fix: Keep the bed evenly moist through the weeks right after tubers set, rotate away from potatoes, and pick a scab-resistant variety next time.
Your season math: Michigan gives potatoes about 156 frost-free days, and it needs roughly 90 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting potatoes in Michigan: questions
When should I plant potatoes in Michigan?+
In a typical Michigan year, sow potatoes between Mar 28 to Apr 30, keyed to the state's median last frost around May 5. There's also a fall window: Jun 20 to Jul 3. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is Michigan?+
Michigan spans zones 4b–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 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.