Root Vegetable

When to Plant Sweet Potatoes in Michigan

Not related to regular potatoes at all. Sweet potatoes need heat and a long growing season but reward with incredible harvests.

The Short Answer

Sweet potatoes in Michigan require real commitment — the crop needs 90+ days of warm growing conditions that Michigan's compressed season barely provides. But southern Michigan gardeners with raised beds and black plastic mulch can grow them successfully, and the novelty of homegrown sweet potatoes from a Michigan garden makes the effort worthwhile.

Michigan Frost Dates

Your planting dates depend on which part of Michigan you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Upper Peninsula 4a, 4b, 5a May 15 - Jun 5 Sep 10 - Sep 25
Northern Lower Michigan 5a, 5b May 10 - May 25 Sep 20 - Oct 5
Southern Michigan 5b, 6a, 6b Apr 25 - May 10 Oct 1 - Oct 15

Sweet Potatoes Planting Schedule for Michigan

Upper Peninsula (Zones 4a, 4b, 5a)

Average last frost: May 15 - Jun 5 · Average first frost: Sep 10 - Sep 25

Start Seeds Indoors
8 wks before frost
Transplant Outside
3 wks after frost

Northern Lower Michigan (Zones 5a, 5b)

Average last frost: May 10 - May 25 · Average first frost: Sep 20 - Oct 5

Start Seeds Indoors
8 wks before frost
Transplant Outside
3 wks after frost

Southern Michigan (Zones 5b, 6a, 6b)

Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15

Start Seeds Indoors
8 wks before frost
Transplant Outside
3 wks after frost

Growing Sweet Potatoes in Michigan

State-Specific Growing Tips

Plant slips in early June when soil reaches 65°F. Black plastic mulch is mandatory — it can raise soil temperature by 10-15°F, which makes or breaks sweet potato production in Michigan. Raised beds over heavy clay. Choose the shortest-season varieties available. Harvest before first frost — this is critical in Michigan where frost can arrive in mid-September in the north. Cure at 80-85°F for 10 days.

Recommended Varieties for Michigan

Beauregard (90 days) is the only reliable choice for Michigan. Bush Porto Rico for compact spaces. MSU Extension notes sweet potatoes are experimental in most of Michigan and recommends starting with just a few slips to test your conditions.

Common Challenges in Michigan

Season length is the fundamental challenge. Cool nights below 55°F slow growth dramatically. Early frost can catch unharvested tubers. Michigan's clay soils must be heavily amended for sweet potato success.

Growing Tips

Grow from slips, not seeds. Start slips from a sweet potato in water 8 weeks before transplanting. Cure harvested tubers in warmth for 10 days.

Companion Planting

Plant sweet potatoes alongside these companions for better growth:

Beans Corn

Keep sweet potatoes away from:

Squash

The Bottom Line

Sweet Potatoes can be grown successfully in Michigan with proper attention to regional frost dates and local growing conditions. Timing varies across the state — Upper Peninsula gardeners work with a last frost around May 15 - Jun 5, while Southern Michigan sees frost end around Apr 25 - May 10. Choose varieties suited to your region, amend your soil based on its specific needs, and monitor for the pests and diseases most common in your area. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Sweet Potatoes Growing Guide National planting guide with all states Michigan Planting Calendar All plants for Michigan Sweet Potatoes in Alabama Alabama planting dates Sweet Potatoes in Alaska Alaska planting dates Sweet Potatoes in Arizona Arizona planting dates Sweet Potatoes in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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