Minnesota’s harsh winters mean mint should wait until early June, when the soil has fully thawed and warmed. The best time to plant mint in minnesota is after the last frost date, typically between late May and early June, when nighttime temperatures stay above 50°F.
Mint is a tough perennial that can survive Minnesota winters, but it needs a proper start. Planting too early risks frost damage. Planting too late means weak roots before winter. This guide covers everything you need for successful mint planting in the North Star State.
Why Timing Matters For Mint In Minnesota
Mint is hardy but not invincible. Minnesota’s climate zone ranges from 3a to 4b. That means cold winters and short growing seasons. If you plant mint too early, cold soil can stunt growth or kill young plants. If you plant too late, roots won’t establish before frost.
The sweet spot is when soil temperatures reach at least 60°F. In most Minnesota counties, this happens around late May to early June. Check your local frost dates using the Minnesota DNR’s frost map or your county extension office.
Understanding Minnesota’s Frost Dates
Northern Minnesota (Duluth, Bemidji) has a last frost around May 20–June 5. Southern Minnesota (Rochester, Mankato) sees last frost around May 1–15. Twin Cities metro falls in between, usually May 10–20.
Mint is somewhat frost-tolerant, but young transplants are vulnerable. A late May freeze can kill tender new growth. Always wait until after your area’s average last frost date.
Soil Temperature Requirements
Mint prefers soil temps between 60°F and 70°F for optimal germination and root growth. You can check soil temperature with a simple probe thermometer. Insert it 2–3 inches deep in the morning. If it reads below 55°F, wait another week.
In Minnesota, soil warms slowly. Black plastic or row covers can help warm the soil a few degrees. But don’t rush it. Cold, wet soil leads to root rot.
Best Time To Plant Mint In Minnesota
Now let’s get specific. The exact best time to plant mint in Minnesota depends on your method: seeds, transplants, or cuttings. Each has its own timeline.
Planting Mint From Seeds
Mint seeds are tiny and slow to germinate. Start them indoors 8–10 weeks before your last frost date. For most of Minnesota, that means starting seeds in early to mid-March.
- Fill seed trays with moist seed-starting mix.
- Sprinkle seeds on top. Don’t cover them—mint needs light to germinate.
- Mist gently and cover with plastic wrap.
- Place in a warm spot (65–70°F) with bright indirect light.
- Seeds germinate in 10–15 days.
- Remove plastic once sprouts appear.
- Transplant outdoors after hardening off for 7–10 days.
Hardening off means gradually exposing seedlings to outdoor conditions. Start with 1 hour of shade, then increase daily over a week. This prevents transplant shock.
Planting Mint Transplants
Nursery transplants are the easiest route. Buy healthy mint plants from local garden centers in late May or early June. Look for plants with bright green leaves and no yellowing.
Plant them after all frost danger passes. In southern Minnesota, that’s around May 15. In the north, wait until June 1–5. Dig a hole twice the width of the root ball. Place the plant at the same depth it was in the pot. Water thoroughly.
Planting Mint Cuttings Or Divisions
If you have existing mint, you can divide it in spring. Wait until new growth appears, usually mid-May. Dig up the plant, separate roots into sections with at least 3–4 shoots each. Replant immediately.
Cuttings from a friend’s plant work too. Take 4–6 inch stems, remove lower leaves, and place in water. Roots appear in 1–2 weeks. Transplant after roots are 1–2 inches long, but wait until June for outdoor planting.
Preparing Your Minnesota Mint Bed
Mint is invasive. It spreads aggressively through underground runners. In Minnesota’s short season, this is actually helpful—it fills in fast. But you must contain it.
Choosing The Right Location
Mint grows best in partial shade to full sun. In Minnesota, afternoon shade is beneficial during July heat waves. Morning sun with afternoon shade is ideal.
Avoid low spots where water pools. Mint likes moist soil but not soggy roots. Raised beds work well in heavy clay soils common in Minnesota.
Soil Preparation
Mint prefers rich, loamy soil with a pH between 6.0 and 7.0. Test your soil with a simple kit from any garden center. If pH is too low, add lime. If too high, add sulfur.
Work in 2–3 inches of compost before planting. This improves drainage and adds nutrients. In sandy soils, add peat moss to retain moisture. In clay soils, add coarse sand or perlite.
Containment Strategies
Mint will take over your garden if not controlled. Use these methods:
- Plant in containers sunk into the ground. Use a 5-gallon bucket with drainage holes. Bury it so the rim is 1 inch above soil level.
- Use underground barriers. Bury 12-inch deep plastic or metal edging around the bed.
- Plant mint in raised beds with solid bottoms.
- Harvest frequently to keep growth in check.
Even with barriers, mint may escape. Check edges monthly and pull any runners that cross the line.
Step-By-Step Planting Guide
Here’s the exact process for planting mint in Minnesota, timed for early June.
Step 1: Choose Your Planting Date
Check your local forecast. Look for a 7-day stretch with nighttime lows above 50°F. For most of Minnesota, this occurs between May 25 and June 10. Write down your target date.
Step 2: Prepare The Bed
One week before planting, clear the area of weeds. Loosen soil to 8–10 inches deep. Mix in 2 inches of compost. Rake smooth. Water lightly if soil is dry.
Step 3: Harden Off Plants
If you started seeds indoors, begin hardening off 7–10 days before planting. Move trays outside for 1–2 hours in shade. Increase time and sun exposure daily. Bring indoors if frost is forecast.
Step 4: Plant
On your chosen date, dig holes 18–24 inches apart. For containers, use one plant per 12-inch pot. Place each plant at the same depth as in its pot. Backfill with soil and press gently.
Step 5: Water Thoroughly
Water immediately after planting. Give each plant 1–2 cups of water. Keep soil consistently moist for the first two weeks. After that, water when the top inch of soil feels dry.
Step 6: Mulch
Apply 2–3 inches of organic mulch around plants. Straw, shredded leaves, or wood chips work well. Mulch keeps soil cool, retains moisture, and suppresses weeds. In Minnesota, it also protects roots from early fall frosts.
Caring For Mint After Planting
Mint is low-maintenance, but a little care goes a long way in Minnesota’s climate.
Watering Schedule
Mint needs consistent moisture. During dry spells, water deeply once or twice a week. Aim for 1–1.5 inches of water per week. Use a rain gauge to track rainfall. In sandy soils, water more frequently.
Overwatering causes root rot. If leaves turn yellow or stems get mushy, reduce watering. Improve drainage by adding compost or moving plants to raised beds.
Fertilizing
Mint is not a heavy feeder. Too much fertilizer reduces flavor. Apply a balanced 10-10-10 fertilizer once in early summer. Use half the recommended rate. Or side-dress with compost in midsummer.
Avoid high-nitrogen fertilizers. They produce lush leaves with weak flavor. Organic options like fish emulsion or seaweed extract work well.
Pruning And Harvesting
Start harvesting once plants are 6–8 inches tall. Pinch off the top 2–3 inches of stems. This encourages bushy growth. Never remove more than one-third of the plant at once.
Regular harvesting prevents flowering. Once mint flowers, leaves become less flavorful. In Minnesota, mint blooms in late July or August. Keep cutting to delay flowering.
Winter Protection
Mint dies back to the ground in Minnesota winters. It regrows from roots in spring. To protect roots from extreme cold, apply 4–6 inches of mulch after the ground freezes. Use straw, leaves, or evergreen boughs.
In containers, mint is less hardy. Move pots to an unheated garage or bury them in the ground for winter. Water occasionally if soil is dry.
Common Mint Varieties For Minnesota
Not all mint varieties perform equally in Minnesota’s climate. Here are the best options.
Peppermint (Mentha × Piperita)
Peppermint is very cold-hardy. It survives zone 3 winters with mulch. Strong flavor for teas and desserts. Grows 2–3 feet tall. Spreads aggressively.
Spearmint (Mentha Spicata)
Spearmint is slightly less hardy but still reliable in Minnesota. Milder flavor than peppermint. Great for mojitos and salads. Grows 1–2 feet tall.
Apple Mint (Mentha Suaveolens)
Apple mint has fuzzy leaves and a fruity scent. Hardy to zone 4. Needs extra winter mulch in northern Minnesota. Grows 2–3 feet tall.
Chocolate Mint (Mentha × Piperita ‘Chocolate’)
A peppermint variety with chocolate undertones. Hardy to zone 3. Good for desserts and teas. Same growth habits as peppermint.
Pineapple Mint (Mentha Suaveolens ‘Variegata’)
Pineapple mint has variegated leaves and a mild pineapple scent. Less hardy than others. Best grown in containers that can be moved indoors. Zone 5 minimum.
Troubleshooting Common Mint Problems
Even in Minnesota, mint faces issues. Here’s how to handle them.
Yellow Leaves
Yellow leaves usually mean overwatering or poor drainage. Check soil moisture. If soggy, stop watering until top 2 inches dry out. Improve drainage with compost or move to raised bed.
Yellow leaves can also indicate nitrogen deficiency. Apply a balanced fertilizer at half strength. Leaves should green up within a week.
Leggy Growth
Leggy mint means insufficient light. Move plants to a sunnier spot. In Minnesota, morning sun with afternoon shade is best. Prune leggy stems back by half to encourage bushiness.
Pests
Mint repels many pests, but a few still attack. Watch for:
- Aphids: Small green insects on new growth. Spray with water or insecticidal soap.
- Spider mites: Fine webbing on leaves. Increase humidity or use neem oil.
- Cutworms: Chewed stems at soil level. Use cardboard collars around young plants.
Most pests are minor. Healthy mint outgrows damage quickly.
Rust Disease
Mint rust appears as orange spots on leaf undersides. Remove infected leaves immediately. Improve air circulation by spacing plants farther apart. Avoid overhead watering. In severe cases, remove and destroy affected plants.
Harvesting And Storing Mint
Mint harvest peaks in July and August. Here’s how to get the most from your plants.
When To Harvest
Harvest in the morning after dew dries. Essential oils are strongest then. Pick leaves before flowers open for best flavor. In Minnesota, this means harvesting by mid-July.
How To Harvest
Use clean scissors or pinch with fingers. Cut stems 2–3 inches above the ground. Leave at least one-third of the plant to regrow. Harvest every 2–3 weeks during growing season.
Storing Fresh Mint
Store fresh mint in the refrigerator. Place stems in a glass of water, cover with a plastic bag, and refrigerate. Change water every 2 days. Fresh mint lasts 1–2 weeks.
Alternatively, wrap leaves in damp paper towels and store in a sealed bag. Use within 5–7 days.
Drying Mint
Dry mint for winter use. Tie stems in small bundles and hang upside down in a dark, dry, well-ventilated area. Mint dries in 1–2 weeks. Crumble leaves into jars and store in a cool, dark place.
Dried mint lasts 1–2 years. Flavor fades over time, so use within 6 months for best taste.
Freezing Mint
Freezing preserves flavor better than drying. Chop fresh leaves and pack into ice cube trays. Cover with water or olive oil. Freeze, then transfer cubes to freezer bags. Use in teas, sauces, or smoothies.
Frozen mint lasts 6–8 months. No need to thaw before using.
Using Mint In Minnesota Gardens
Mint isn’t just for cooking. Use it strategically in your garden.
Companion Planting
Mint repels ants, aphids, and cabbage moths. Plant near cabbage, tomatoes, or peppers. Keep mint contained—it will choke out neighbors if allowed to spread.
Avoid planting mint near parsley or chamomile. These plants don’t compete well with mint’s aggressive roots.
Ground Cover
Use mint as a living mulch under shrubs or trees. It suppresses weeds and stays green all summer. Choose a less aggressive variety like apple mint. Keep it away from lawns—it spreads into grass.
Container Gardening
Mint thrives in containers. Use pots at least 12 inches wide with drainage holes. Place in partial shade. Water daily in hot weather. Bring containers indoors before first frost for year-round mint.
In Minnesota, containers freeze solid in winter. Move pots to an unheated garage or bury them in a protected spot. Water occasionally if soil thaws.
Frequently Asked Questions
Can I Plant Mint In Fall In Minnesota?
Fall planting is risky. Mint needs 6–8 weeks to establish before ground freezes. In Minnesota, that means planting by early September. Even then, winter survival is uncertain. Spring planting is more reliable.
How Late Can I Plant Mint In Minnesota?
You can plant mint until mid-July. Later than that, roots won’t establish before winter. If you miss the window, start seeds indoors in late summer and overwinter plants indoors. Transplant next spring.
Does Mint Come Back Every Year In Minnesota?
Yes, mint is perennial in Minnesota. It dies back to the ground in winter and regrows from roots in spring. Mulch helps protect roots from extreme cold. Most varieties survive zone 3 winters with proper care.
Should I Plant Mint In Sun Or Shade In Minnesota?
Mint grows best in partial shade in Minnesota. Morning sun with afternoon shade prevents leaf scorch during July heat. Full sun works if soil stays moist. Full shade results in leggy growth.
Can I Grow Mint Indoors In Minnesota?
Yes, mint grows well indoors. Use a south-facing window or grow lights. Keep soil moist but not soggy. Harvest regularly to keep plants compact. Indoor mint provides fresh leaves year-round.
Final Tips For Minnesota Mint Success
Planting mint at the right time sets you up for success. Remember these key points:
- Wait until soil reaches 60°F, usually early June.
- Harden off transplants for 7–10 days.
- Contain mint with barriers or containers.
- Water consistently, especially during dry spells.
- Harvest frequently to promote bushy growth.
- Mulch heavily before winter for root protection.
Mint is one of the easiest herbs to grow in Minnesota. Once established, it provides fresh leaves for teas, cooking, and garnishes from June through October. With proper timing and care, your mint patch will thrive for years.
Start planning your mint bed now. Check your local frost dates, prepare the soil,