Jicama in Wisconsin requires a long warm season, so start seeds indoors in early spring for transplanting after frost. Finding the best time to plant jicama in wisconsin is crucial because this root vegetable needs about 150 to 180 frost-free days to mature fully. Wisconsin’s short growing season means you have to plan carefully, but with the right timing, you can harvest your own crisp, sweet jicama by early fall.
This guide covers everything from indoor seed starting to transplanting and harvest. You will learn the exact dates, soil temperatures, and steps to succeed with jicama in your Wisconsin garden.
Best Time To Plant Jicama In Wisconsin
The best time to plant jicama in Wisconsin is indoors, about 8 to 10 weeks before your last expected spring frost. For most of Wisconsin, that means starting seeds between late February and mid-March. Transplant the seedlings outdoors only after all danger of frost has passed and the soil has warmed to at least 60°F, which typically happens from late May to early June.
Jicama is extremely sensitive to cold. Even a light frost can kill the plants or damage the tubers. That is why starting indoors is non-negotiable in Wisconsin’s climate.
Understanding Wisconsin’s Growing Zones
Wisconsin spans USDA hardiness zones 3b to 5b. The last frost date varies significantly across the state:
- Southern Wisconsin (zones 5a-5b): Last frost around May 1-15
- Central Wisconsin (zone 4b-5a): Last frost around May 15-25
- Northern Wisconsin (zones 3b-4a): Last frost around May 25-June 5
Your specific location determines the exact planting window. Always check your local frost dates using the Wisconsin State Climatology Office or a reliable gardening app.
Why Indoor Starting Is Essential
Jicama seeds need warmth to germinate—soil temperatures between 70°F and 85°F. Wisconsin’s spring soil is far too cold for direct sowing. Starting indoors gives you a head start of two months, which is often the difference between a harvest and a failure.
Indoor starting also protects young seedlings from unexpected cold snaps, pests, and uneven moisture. You control the environment completely.
Step-By-Step Indoor Seed Starting
- Fill seed trays or small pots with a sterile seed-starting mix.
- Sow jicama seeds about 1/2 inch deep, one seed per cell or pot.
- Water gently and cover with a humidity dome or plastic wrap.
- Place in a warm spot, ideally 75-85°F. A heat mat helps.
- Seeds germinate in 7-14 days. Remove cover once sprouts appear.
- Provide 14-16 hours of bright light daily. A grow light works best.
- Keep soil moist but not waterlogged.
Transplant seedlings into larger pots if they outgrow their containers before outdoor planting time. Harden them off gradually over 7-10 days before moving them outside.
Soil Preparation For Jicama
Jicama grows best in loose, well-draining soil with a pH between 6.0 and 7.0. Heavy clay or compacted soil will produce misshapen or stunted tubers. Prepare your garden bed in early spring, as soon as the soil is workable.
Follow these steps:
- Loosen the soil to at least 12 inches deep.
- Mix in 2-3 inches of aged compost or well-rotted manure.
- Remove rocks, roots, and debris that could block tuber growth.
- Consider raised beds if your native soil is heavy clay.
Jicama is a heavy feeder. Add a balanced fertilizer (10-10-10) at planting time, following package directions.
Transplanting Jicama Outdoors
Wait until nighttime temperatures stay above 55°F consistently. In most of Wisconsin, this happens between late May and early June. Check the 10-day forecast before transplanting.
Space plants 12-18 inches apart in rows 24-36 inches apart. Jicama vines can spread 6-10 feet, so give them room. Install a trellis or support system at planting time to keep vines off the ground.
Water deeply after transplanting. Mulch around the base to retain moisture and suppress weeds. Jicama needs consistent moisture, especially during tuber formation.
Ideal Soil Temperature For Transplanting
Use a soil thermometer to check the temperature at 4 inches deep. The soil should be at least 60°F, but 65-70°F is better. If the soil is too cold, delay planting by a week or two.
Cold soil stunts growth and can cause root rot. In Wisconsin, soil warms slowly, so be patient.
Growing Jicama Through The Wisconsin Summer
Jicama thrives in heat. Wisconsin summers, especially July and August, provide the warmth this plant needs. However, the growing season is still short, so you must maximize every warm day.
Watering And Fertilizing
Jicama needs about 1-2 inches of water per week. Consistent moisture is critical during tuber bulking, which happens from mid-summer onward. Drip irrigation or soaker hoses work well.
Fertilize every 3-4 weeks with a low-nitrogen fertilizer (5-10-10) once the vines start running. Too much nitrogen encourages leafy growth at the expense of tubers.
Pest And Disease Management
In Wisconsin, jicama faces few serious pests. Aphids, spider mites, and whiteflies can appear. Use insecticidal soap or neem oil if needed. Deer and rabbits may nibble young plants, so fencing helps.
Fungal diseases like powdery mildew can occur in humid conditions. Ensure good air circulation by spacing plants properly and pruning excess foliage.
Harvesting Jicama Before Frost
Jicama tubers are ready to harvest when the vines begin to yellow and die back, typically 150-180 days after planting. In Wisconsin, this is usually late September to early October. You must harvest before the first hard frost, which can arrive as early as mid-September in northern areas.
To harvest:
- Cut back the vines first.
- Gently dig around the base with a garden fork.
- Pull up the tubers carefully to avoid bruising.
- Brush off excess soil, but do not wash until ready to eat.
Jicama stores well in a cool, dark place for several weeks. Keep them at 50-60°F with moderate humidity.
Signs Your Jicama Is Ready
Mature tubers are typically 4-6 inches in diameter and weigh 1-3 pounds. They should feel firm and heavy. If the weather threatens frost and the tubers are still small, harvest anyway—they are still edible, just smaller.
Do not leave jicama in the ground after a frost. Frozen tubers become mushy and rot quickly.
Common Challenges For Wisconsin Gardeners
Growing jicama in Wisconsin is possible, but you will face some hurdles. Here are the most common issues and how to handle them.
Short Growing Season
Wisconsin’s frost-free period ranges from 120 days in the north to 160 days in the south. Jicama needs 150-180 days. To compensate, start seeds as early as possible indoors and use season extenders like row covers or cold frames in early spring and late fall.
Choose early-maturing jicama varieties if available. Standard jicama is usually the only option, but some seed companies offer faster-growing strains.
Cool Summer Temperatures
Even in summer, Wisconsin can have cool spells. Jicama grows best when daytime temperatures are consistently above 75°F. If a cool, cloudy summer occurs, growth slows. Black plastic mulch can warm the soil slightly.
Plant in the sunniest spot in your garden. South-facing slopes or areas near a south-facing wall provide extra warmth.
Soil Compaction
Wisconsin’s clay soils can be problematic. Jicama tubers need loose soil to expand. Raised beds or deep tilling with plenty of organic matter solve this. Consider growing in large containers or grow bags if your soil is very heavy.
Containers should be at least 12 inches deep and 18 inches wide. Use a high-quality potting mix.
Frequently Asked Questions
Can I Plant Jicama Seeds Directly In The Ground In Wisconsin?
Direct sowing is not recommended. The soil is too cold until late spring, and the growing season is too short. Always start seeds indoors 8-10 weeks before the last frost.
What Happens If I Plant Jicama Too Late In Wisconsin?
Late planting means the tubers may not mature before the first fall frost. You will end up with small, underdeveloped jicama. Stick to the indoor start schedule for best results.
How Do I Protect Jicama From Early Frost In Wisconsin?
Use row covers, frost blankets, or cloches when frost is forecast. Harvest immediately if a hard freeze is expected. You can also plant in a sheltered location near a building for added warmth.
Is Jicama Worth Growing In Northern Wisconsin?
It is more challenging but possible with careful timing and season extenders. Northern gardeners should start seeds even earlier (late February) and use every tool to extend the season. Success rates are lower than in southern Wisconsin.
Can I Grow Jicama In A Container In Wisconsin?
Yes, containers work well. Use a large pot (at least 5 gallons) with drainage holes. Move the container indoors or to a sheltered spot if frost threatens. This gives you more control over the growing environment.
Final Tips For Success
Growing jicama in Wisconsin takes planning, but the reward is worth it. Start seeds indoors on time, monitor soil temperatures, and protect plants from cold. With the best time to plant jicama in wisconsin being late winter indoors and late spring outdoors, you can enjoy homegrown jicama by early autumn.
Keep a garden journal to track your planting dates, weather patterns, and harvest results. Each year, you will refine your timing and technique. Jicama is a conversation starter in Wisconsin gardens—few people grow it, so you will stand out.
Remember that patience is key. Jicama grows slowly at first, but once summer heat arrives, the vines take off. Water consistently, watch for pests, and harvest before frost. Your effort will be rewarded with crisp, sweet tubers that taste nothing like store-bought versions.
If you have questions about your specific location, contact your local Wisconsin Extension office. They can provide microclimate advice and frost date data. Happy planting!