Minnesota’s cold climate makes it necessary to start jicama seeds indoors by mid-April for a successful outdoor transplant. Finding the best time to plant jicama in minnesota is crucial because this tropical root vegetable needs a long, warm growing season that our state simply doesn’t provide naturally.
Jicama (Pachyrhizus erosus) is a warm-season crop that requires about 150 to 180 frost-free days to mature. In Minnesota, our growing season typically ranges from 120 to 160 days, depending on your specific zone. That’s why timing is everything.
Best Time To Plant Jicama In Minnesota
The absolute best window to start jicama seeds indoors is between April 10 and April 25. This gives you enough time to grow strong seedlings before transplanting them outdoors after the last frost date, which in Minnesota usually falls between May 15 and May 30.
If you start too early, your seedlings become leggy and root-bound. Start too late, and your jicama won’t have enough time to develop those crisp, sweet tubers before the first fall frost hits.
Understanding Minnesota’s Growing Zones
Minnesota spans USDA hardiness zones 3a through 5a. The Twin Cities area sits in zone 4b, while northern parts like Duluth are zone 3b or 4a. Southern Minnesota, near the Iowa border, is zone 5a.
Your specific location affects the best planting time. Here’s a quick breakdown:
- Zone 3a-3b (northern Minnesota): Start seeds April 10-15, transplant June 1-10
- Zone 4a-4b (central Minnesota): Start seeds April 15-20, transplant May 25-June 5
- Zone 5a (southern Minnesota): Start seeds April 20-25, transplant May 20-30
Why Indoor Starting Is Non-Negotiable
Direct sowing jicama seeds outdoors in Minnesota is almost always a failure. The soil temperature needs to be consistently above 65°F for germination, which doesn’t happen here until early June. By then, you’ve lost precious growing weeks.
Starting indoors gives you a 6-8 week head start. Your seedlings will be 4-6 inches tall with several true leaves by transplant time. That’s the size needed to survive and thrive in our short season.
Step-By-Step Indoor Starting Guide
Materials You’ll Need
- Jicama seeds (soak overnight before planting)
- Seed-starting mix (light and well-draining)
- 4-inch pots or cell trays
- Heat mat (optional but recommended)
- Grow lights or a sunny south-facing window
- Plastic dome or plastic wrap for humidity
Planting Process
- Soak seeds in warm water for 12-24 hours to soften the hard seed coat
- Fill pots with moistened seed-starting mix
- Plant seeds 1/2 inch deep, one per pot
- Cover with plastic to maintain humidity
- Place on heat mat set to 75-80°F
- Remove plastic once seedlings emerge (7-14 days)
- Move to bright light immediately
- Keep soil consistently moist but not waterlogged
Light And Temperature Management
Jicama seedlings need 14-16 hours of bright light daily. Without enough light, they stretch and become weak. Use grow lights positioned 2-3 inches above the plants, raising them as the seedlings grow.
Keep daytime temperatures around 70-75°F and nighttime temperatures no lower than 60°F. Cooler temps slow growth and can cause stunting.
Hardening Off Your Jicama Seedlings
About two weeks before your planned transplant date, start hardening off your seedlings. This gradual acclimation to outdoor conditions prevents transplant shock.
- Day 1-2: Place seedlings outside in shade for 1 hour
- Day 3-4: Increase to 2 hours in partial shade
- Day 5-6: Move to morning sun for 3 hours
- Day 7-8: Full morning sun for 4 hours
- Day 9-10: Afternoon sun for 5 hours
- Day 11-12: Full sun all day, bring in at night
- Day 13-14: Leave out overnight if temps stay above 50°F
Skip hardening off if you’re using a cold frame or greenhouse. Just open the vents gradually over a week.
Transplanting Outdoors
Preparing The Garden Bed
Jicama needs full sun and loose, well-draining soil. Raised beds work excellent in Minnesota because they warm up faster in spring. Mix in 2-3 inches of compost or well-rotted manure before planting.
Soil pH should be between 6.0 and 7.0. Test your soil and amend if needed. Jicama is a heavy feeder, so incorporate a balanced organic fertilizer (10-10-10) at planting time.
Spacing And Planting Depth
- Space plants 12-18 inches apart in rows 3 feet apart
- Plant at the same depth they were growing in pots
- Water thoroughly after transplanting
- Apply a 2-inch layer of organic mulch to retain moisture and suppress weeds
Using Season Extenders
In Minnesota, using season extenders can make the difference between a harvest and a failure. Consider these options:
- Black plastic mulch: Warms soil by 5-10°F, speeds early growth
- Row covers: Protect from cold snaps and pests
- Low tunnels: Extend the season by 2-4 weeks on each end
- Wall o’ water: Individual plant protectors for early transplanting
Care Throughout The Growing Season
Watering
Jicama needs consistent moisture, especially during tuber formation. Water deeply 1-2 times per week, providing about 1 inch of water each time. Drip irrigation is ideal because it keeps foliage dry and reduces disease risk.
Mulch helps retain moisture and keeps soil temperatures stable. In Minnesota’s hot July and August, mulched soil stays 10-15°F cooler than bare soil.
Fertilizing
Side-dress with compost or a low-nitrogen fertilizer (5-10-10) when plants are 12 inches tall. Too much nitrogen encourages leafy growth at the expense of tuber development. Switch to a phosphorus-rich fertilizer once flowers appear.
Pest And Disease Management
Common Minnesota pests for jicama include:
- Aphids: Spray with neem oil or insecticidal soap
- Spider mites: Increase humidity and use miticides if severe
- Slugs and snails: Use diatomaceous earth or beer traps
- Cutworms: Place cardboard collars around stems at transplant
Diseases are rare but watch for powdery mildew in humid conditions. Ensure good air circulation and avoid overhead watering.
Harvesting Jicama In Minnesota
When To Harvest
Jicama is ready to harvest 150-180 days after planting. In Minnesota, that means harvesting typically happens in late September to mid-October, just before the first hard frost.
Signs of maturity include:
- Yellowing and dying back of vines
- Firm, round tubers 4-6 inches in diameter
- Skin that’s light brown and slightly rough
How To Harvest
- Cut vines back to 6 inches above the ground
- Use a garden fork to loosen soil around plants
- Gently lift tubers from the soil
- Brush off excess dirt, don’t wash
- Cure in a warm, dry place for 1-2 weeks
Storage Tips
Properly cured jicama stores for 2-3 months in a cool, dark place. Ideal storage conditions are 50-60°F with 60-70% humidity. A root cellar or basement works well. Don’t refrigerate whole jicama; it damages the texture.
Cut jicama should be wrapped in plastic and refrigerated, where it keeps for about a week.
Common Mistakes And Solutions
Planting Too Early Outdoors
Many Minnesota gardeners get eager and transplant jicama in early May. Then a late frost kills the plants. Always wait until soil temperature reaches 65°F and all frost danger has passed.
Overwatering
Jicama roots rot easily in waterlogged soil. Let the top inch of soil dry between waterings. If you’re using mulch, reduce watering frequency.
Ignoring Day Length
Jicama is a short-day plant, meaning it forms tubers when day length drops below 12 hours. In Minnesota, this happens naturally in late August and September. Don’t try to extend daylight with artificial lights; it will delay tuber formation.
Not Providing Support
Jicama vines can grow 10-15 feet long. Provide a trellis or stakes for them to climb. This improves air circulation and makes harvesting easier.
Varieties That Work Best In Minnesota
Not all jicama varieties are created equal for our short season. Look for these early-maturing types:
- ‘San Juan’ – Matures in 150 days, reliable in cool climates
- ‘Crystal’ – 160 days, crisp and sweet
- ‘Mexican Yam Bean’ – 155 days, traditional variety
- ‘Early White’ – 145 days, best for northern zones
Avoid late-maturing varieties like ‘Giant’ or ‘Large Leaf’ that need 200+ days. They won’t produce tubers before frost.
Frequently Asked Questions
Can I Plant Jicama Seeds Directly In The Ground In Minnesota?
It’s not recommended. Direct sowing usually fails because soil temperatures don’t warm enough until June, leaving insufficient time for tuber development. Always start seeds indoors 6-8 weeks before your last frost date.
What Happens If I Plant Jicama Too Late In Minnesota?
Late planting results in small or no tubers. Jicama needs the long days of summer for vine growth and the shorter days of late summer for tuber formation. Planting after mid-June gives the plant less than 100 days before frost, which is not enough.
Do I Need To Prune Jicama Vines?
No, pruning isn’t necessary. Let the vines grow freely. However, you can pinch off flower buds to redirect energy to tuber growth. This is optional but can increase yield.
Can Jicama Survive A Light Frost?
No. Jicama is extremely frost-sensitive. Even a light frost (32°F) will kill the vines and damage the tubers. Harvest before the first frost or cover plants if a frost is forecast.
How Do I Know If My Jicama Is Ready To Harvest?
The vines will start yellowing and dying back in late September or October. Gently dig around the base of a plant to check tuber size. They should be at least 4 inches in diameter. If they’re smaller, wait a bit longer, but don’t wait past the first frost.
Final Tips For Success
Growing jicama in Minnesota is challenging but rewarding. The key is timing. Start seeds indoors by mid-April, transplant after frost danger passes, and use season extenders to maximize your growing window.
Keep a garden journal noting your planting dates, weather patterns, and harvest results. This helps you refine your timing each year. With practice, you’ll be enjoying homegrown jicama from your Minnesota garden.
Remember that jicama is a tropical plant, so it needs warmth, consistent moisture, and patience. But the payoff—crisp, sweet tubers that taste nothing like store-bought—is worth the effort.
If you have a short growing season in northern Minnesota, consider growing jicama in containers that can be moved indoors if early frost threatens. Large 5-gallon pots work well and give you more control over soil temperature.
Don’t get discouraged if your first attempt yields small tubers. Each season teaches you something new. Focus on the timing, and you’ll improve every year.