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The best time to plant sweet potatoes in Minnesota is late May through mid-June, once the soil has warmed to at least 60°F.
Getting the timing right for when to plant sweet potatoes in Minnesota is the single most important factor for a successful harvest in our short growing season.
These warm-weather crops absolutely hate cold soil and frost, so waiting for consistent warmth is non-negotiable.
In this post, we’ll dig into the ideal planting window, how to prep your garden, and the best varieties for Minnesota’s climate.
Let’s get those sweet potatoes growing.
When to Plant Sweet Potatoes in Minnesota
The question of when to plant sweet potatoes in Minnesota comes down to soil temperature, not just the calendar date.
While the average last frost date in southern Minnesota is around mid-May, sweet potatoes need warmer conditions than many other garden crops.
Planting sweet potatoes in Minnesota too early, when the soil is still chilly, causes the slips to rot or stay stunted in the ground.
That’s why soil temperature should be your main guide for when to plant sweet potatoes in Minnesota.
1. Target Soil Temperature for Planting
Sweet potato slips should go into the ground only when the soil has warmed to a minimum of 60°F, with 65°F to 70°F being even better.
You can check this with a simple soil thermometer inserted a few inches deep.
In Minnesota, the soil usually reaches this temperature around late May in the southern part of the state.
Northern Minnesota might need to wait until early to mid-June.
So if you’re wondering when to plant sweet potatoes in Minnesota, always prioritize soil warmth over a fixed date on the calendar.
2. Using Black Plastic to Warm Soil Early
One of the best tricks for planting sweet potatoes in Minnesota is to pre-warm the soil with black plastic mulch.
Lay the plastic over your raised beds about two weeks before your planned planting date.
This traps solar heat, raising soil temperatures by 5 to 10 degrees.
With this method, you might be able to plant a week or two earlier than you normally could.
Just cut small X-shaped slits in the plastic when you’re ready to set out your slips.
3. Watching the Weather Forecast
Even if the soil feels warm, you need to keep an eye on the nightly forecast.
A late frost in early June is rare but possible in Minnesota, so be ready.
If frost is predicted after you’ve planted, cover your sweet potato slips overnight with row covers or old blankets.
Since sweet potatoes are incredibly sensitive to cold, one frosty night can ruin your entire crop.
So the safest answer for when to plant sweet potatoes in Minnesota is to wait until both soil and air temperatures are reliably warm.
Preparing Your Garden for Sweet Potatoes
Once you’ve nailed the timing for when to plant sweet potatoes in Minnesota, you’ll want to give them the best possible start.
Sweet potatoes love loose, well-draining soil that’s rich in organic matter.
They don’t do well in heavy clay or waterlogged spots.
Here’s how to prep your beds before you plant those slips.
1. Choose the Sunniest Spot
Sweet potatoes need full sun, meaning at least 6 to 8 hours of direct sunlight every single day.
In Minnesota, where the growing season is short, maximizing sun exposure helps the roots bulk up faster.
Pick the warmest, brightest corner of your yard for your sweet potato patch.
Avoid areas near tall trees or buildings that cast shade during any part of the day.
2. Amend the Soil with Compost
Before planting sweet potatoes in Minnesota, mix a few inches of aged compost into the top foot of soil.
This improves drainage while also providing slow-release nutrients.
Avoid fresh manure or high-nitrogen fertilizers, as these will cause lush vines but small, spindly roots.
The goal is balanced soil that encourages root development, not just leafy growth.
3. Space Your Slips Properly
When it’s finally time to plant, space your sweet potato slips about 12 to 18 inches apart.
Leave 3 feet between rows if you’re planting multiple rows.
This gives each plant enough room to spread its vines and produce a good crop.
Plant each slip deep enough to cover the roots and the lower part of the stem, leaving the leaves above the soil.
Water them in well right after planting to settle the soil around the roots.
Best Sweet Potato Varieties for Minnesota
Not all sweet potatoes are created equal when it comes to northern gardens.
Since you’re planting sweet potatoes in Minnesota, you need varieties that mature quickly.
Look for types with a 90 to 100 day maturity window.
1. Beauregard
Beauregard is one of the most popular varieties for northern growers.
It matures in about 90 days, making it a superb choice for Minnesota’s short summer.
It produces large, uniform roots with a deep orange flesh and excellent flavor.
This variety also holds up well in storage, so you can enjoy it through the winter.
2. Georgia Jet
Georgia Jet is another fast-maturing option that does particularly well in cooler climates.
It’s known for producing good yields even when the summer is less than blazing hot.
The roots are moist and sweet, perfect for baking or mashing.
If you’re in northern Minnesota, this is one variety you really should consider.
3. Covington
Covington is slightly slower than Beauregard, taking around 100 days to mature.
It’s still a viable option if you have a long, warm fall.
Covington roots are smooth, sweet, and have a lovely copper skin.
Just make sure you plant as early as you safely can in late May to give it enough time.
Caring for Sweet Potatoes After Planting
Once your sweet potato slips are in the ground, your job is mostly about keeping them warm and watered.
Sweet potatoes are relatively low-maintenance once established.
But there are a few key care steps to keep in mind after planting sweet potatoes in Minnesota.
1. Watering Consistency
Water your sweet potatoes deeply once a week, especially during dry spells.
The goal is to keep the soil consistently moist but never soggy.
Too much water can cause roots to rot, while too little will stress the plants and reduce yields.
A layer of mulch can help retain soil moisture and keep the roots at an even temperature.
2. Skip Heavy Fertilizing
Sweet potatoes don’t need much extra feeding if your soil is already rich with compost.
If you want to give them a boost, use a low-nitrogen fertilizer like a 5-10-10 formulation.
Apply it about three weeks after planting to support root growth.
Avoid over-fertilizing, as that will result in massive vines and puny roots.
So, When to Plant Sweet Potatoes in Minnesota?
When to plant sweet potatoes in Minnesota is all about waiting for warm soil and safe skies.
Planting sweet potatoes in Minnesota should happen in late May to mid-June, once soil temps hit at least 60°F.
Getting the timing right is the key to a bountiful harvest of delicious, homegrown sweet potatoes.
Use black plastic to warm the soil, choose fast-maturing varieties, and keep an eye on the forecast.
With a little patience and planning, you’ll be digging up beautiful sweet potatoes by early fall.
So mark your calendar, watch that soil thermometer, and enjoy the process of growing sweet potatoes in Minnesota.