Washington’s cool, moist climate suits jicama when planted after the soil warms in late spring. The best time to plant jicama in washington is typically from mid-May to early June, once the risk of frost has passed and soil temperatures consistently reach 65°F. This timing gives the long-season crop enough warmth to develop its crisp, edible tubers before fall chill sets in.
Jicama needs about 150 to 200 frost-free days to mature. In Washington, that means you must start seeds indoors or time outdoor planting carefully. Let’s break down exactly when and how to plant jicama across different regions of the state.
Understanding Washington’s Growing Zones For Jicama
Washington spans USDA hardiness zones 4 through 9. Your local climate dictates the planting window. Western Washington near Puget Sound has mild, wet springs. Eastern Washington experiences hotter summers but colder springs.
Check your zone before planting. Jicama is a tropical legume that hates cold soil and frost. Even a light frost can kill young plants or damage developing roots.
Zone-Specific Planting Windows
Here are general guidelines for major Washington regions:
- Western Washington (zones 7-9): Plant outdoors from late May to mid-June. Soil warms slower here due to marine influence.
- Eastern Washington (zones 4-6): Plant from early June to mid-June. Summers are hotter, but spring frosts linger longer.
- Central Washington (zones 6-7): Plant from mid-May to early June. This region has the most reliable warm season.
- Coastal areas (zones 8-9): Plant from late May to early June. Cool ocean breezes can delay soil warming.
Best Time To Plant Jicama In Washington
The exact best time to plant jicama in washington depends on your microclimate. But the safest window is from May 15 to June 10. This period balances soil warmth with enough growing days before first frost.
Jicama seeds need soil temperatures above 60°F to germinate. They grow best when soil is between 65°F and 85°F. If you plant too early, seeds rot or seedlings stall. If you plant too late, tubers won’t mature before frost.
How To Check Soil Temperature
Use a soil thermometer for accuracy. Insert it 4 inches deep in the morning. Wait until readings consistently show 65°F for three consecutive days. In Washington, this often happens after the last spring rain.
You can also use the “hand test”: dig a small hole, grab a handful of soil from 4 inches deep, and squeeze it. If it feels cool and damp, wait. If it feels warm and crumbly, it’s ready.
Starting Seeds Indoors For An Earlier Harvest
Washington’s short growing season makes indoor seed starting almost mandatory. Start seeds 6 to 8 weeks before your planned outdoor planting date. For most of Washington, that means starting seeds indoors in late March or early April.
- Use biodegradable pots to avoid root disturbance during transplanting.
- Plant seeds 1 inch deep in seed-starting mix.
- Keep soil temperature at 70-80°F using a heat mat.
- Provide 14-16 hours of bright light daily.
- Harden off seedlings for 7-10 days before transplanting outdoors.
Preparing Your Garden For Jicama
Jicama needs full sun, loose soil, and consistent moisture. Washington’s clay soils can be problematic. Improve drainage by adding compost or planting in raised beds.
Choose a spot that gets at least 8 hours of direct sunlight daily. Jicama vines can spread 6 to 10 feet, so give them space or provide a trellis.
Soil Requirements
- pH between 6.0 and 7.5
- Well-draining, sandy loam is ideal
- Rich in organic matter
- Free of rocks and large clumps
Test your soil pH before planting. Washington’s acidic soils (especially west of the Cascades) may need lime to raise pH. Add it in fall for best results.
Fertilizing For Strong Growth
Jicama is a light feeder. Too much nitrogen encourages leafy growth at the expense of tubers. Use a balanced fertilizer like 5-10-10 at planting time.
Side-dress with compost or a low-nitrogen fertilizer when vines start to run. Avoid high-nitrogen synthetic fertilizers.
Planting Jicama Outdoors In Washington
Wait for the right moment. The best time to plant jicama in washington is when overnight lows stay above 50°F and daytime highs reach 70°F. This usually aligns with the end of May.
Transplant seedlings on a cloudy day or in late afternoon to reduce transplant shock. Space plants 12 to 18 inches apart in rows 3 to 4 feet apart.
Direct Sowing Vs. Transplanting
Direct sowing is risky in Washington. Seeds need warm soil and consistent moisture. If you must direct sow, wait until soil is at least 65°F and cover with row cover for extra warmth.
Transplanting gives you a 4-6 week head start. Use sturdy seedlings with 4-6 true leaves. Bury them to the same depth as their pots.
Watering Guidelines
Jicama needs consistent moisture, especially during tuber formation. Water deeply once or twice a week, depending on rainfall. Washington’s spring rains often provide enough water early on.
Reduce watering as tubers mature in late summer. Too much water near harvest can cause splitting or bland flavor.
Caring For Jicama Through The Season
Jicama is relatively low-maintenance once established. Focus on weed control, pest management, and supporting the vines.
Weed Control
Keep the planting area weed-free, especially in the first 6 weeks. Jicama has shallow roots that compete poorly with weeds. Use mulch to suppress weeds and retain moisture.
Apply a 2-3 inch layer of organic mulch like straw or shredded leaves after the soil warms. This also helps regulate soil temperature during Washington’s cool nights.
Pest And Disease Management
Common pests in Washington include aphids, slugs, and spider mites. Slugs are especially problematic in western Washington’s damp springs.
- Use beer traps or diatomaceous earth for slugs
- Spray aphids with neem oil or insecticidal soap
- Encourage beneficial insects like ladybugs
- Rotate crops to prevent soil-borne diseases
Jicama is generally disease-resistant. Root rot can occur in poorly drained soil. Ensure good drainage and avoid overwatering.
Supporting The Vines
Jicama vines can grow 10-15 feet long. Provide a sturdy trellis or fence for them to climb. This saves space and improves air circulation.
Train vines onto the support when they are 12 inches tall. Tie them loosely with soft garden twine. Once established, they will climb naturally.
Harvesting Jicama In Washington
Jicama is ready to harvest 150-200 days after planting. In Washington, this usually means late September to early November, just before the first hard frost.
Harvest when the vines begin to yellow and die back. The tubers should be 4-6 inches in diameter. Larger tubers can become woody and less flavorful.
How To Harvest
- Cut back the vines to expose the soil.
- Gently dig around the base of the plant with a garden fork.
- Lift the tubers carefully to avoid bruising.
- Brush off excess soil, but do not wash until ready to use.
Jicama stores well in a cool, dark place for several weeks. Keep them in a paper bag in the refrigerator crisper drawer for up to 2 weeks.
Signs Your Jicama Is Ready
- Vines start to turn yellow and wither
- Tubers feel firm and heavy for their size
- Skin is smooth and light brown
- Flesh is crisp and white when cut
If frost threatens before harvest, cover plants with row cover or harvest immediately. Frost-damaged jicama becomes mushy and unusable.
Common Mistakes When Planting Jicama In Washington
Many gardeners fail because they plant too early or too late. Here are the most common errors to avoid.
Planting Too Early
Washington’s spring is deceptive. A warm week in April can tempt you to plant, but cold soil and late frosts will kill jicama. Always wait until soil is consistently 65°F.
If you plant too early, seeds rot or seedlings get stunted. You lose the entire season. Patience is key.
Planting Too Late
Jicama needs a long growing season. If you plant after June 15 in most of Washington, you risk not having enough frost-free days. The tubers may be small or not form at all.
Start seeds indoors to maximize your window. Even a 2-week delay can mean the difference between a harvest and empty hands.
Ignoring Microclimates
Washington has many microclimates. A garden in Seattle’s urban heat island may be ready 2 weeks earlier than one in the foothills. Observe your own garden’s conditions.
Use a soil thermometer and keep records. Over time, you’ll learn your property’s unique planting windows.
Extending The Growing Season For Jicama
If you live in a cooler part of Washington, use season extenders to push the limits. These tools can add 2-4 weeks to your growing season.
Using Row Covers
Floating row covers protect plants from light frost and warm the soil. Use them in early spring and again in fall. Remove them when temperatures exceed 85°F to prevent overheating.
Row covers also deter pests like flea beetles and aphids. They are cheap and easy to install.
Raised Beds And Black Plastic
Raised beds warm faster than ground soil. Fill them with sandy loam for best drainage. Cover the soil with black plastic 2 weeks before planting to pre-warm it.
Black plastic also suppresses weeds and conserves moisture. Cut slits for planting and leave it in place all season.
Cold Frames Or Mini Greenhouses
For the most protection, use a cold frame or mini greenhouse. Start seeds indoors, then move them to the cold frame 2 weeks before transplanting outdoors.
This method works well for gardeners in zones 4-5. It gives jicama a 4-week head start over direct sowing.
Frequently Asked Questions About Planting Jicama In Washington
Can I Plant Jicama In Washington’s Coastal Areas?
Yes, but you need to start seeds indoors and use season extenders. Coastal areas have cool summers and mild winters. Plant in late May or early June after soil warms. Expect smaller tubers than in warmer regions.
What Happens If I Plant Jicama Too Early In Washington?
Seeds rot in cold, wet soil. Seedlings get stunted or killed by frost. You waste time and money. Always wait until soil temperature reaches 65°F and frost risk is gone.
How Do I Know When Soil Is Warm Enough For Jicama?
Use a soil thermometer. Insert it 4 inches deep at 8 AM. When readings show 65°F for three days in a row, it’s safe. You can also look for consistent nighttime temperatures above 50°F.
Can I Grow Jicama In Containers In Washington?
Yes, use a 5-gallon container with drainage holes. Fill with loose, well-draining potting mix. Place in full sun. Container soil warms faster, which helps in cool climates. Water more frequently than in-ground plants.
What Is The Latest I Can Plant Jicama In Washington?
The latest safe planting date is June 10 for most of Washington. For eastern Washington, you might push to June 15. After that, you risk not having enough frost-free days for tuber development.
Final Tips For Success With Jicama In Washington
Jicama is not the easiest crop for Washington, but it is rewarding. Focus on timing, soil warmth, and season extension. Start seeds indoors without fail.
Choose a sunny, sheltered spot. Use raised beds if your soil is heavy clay. Water consistently but avoid waterlogging. Harvest before the first hard frost.
Remember that the best time to plant jicama in washington is a narrow window. Mark your calendar for mid-May to early June. Check your local frost dates and soil temperature.
With careful planning, you can enjoy fresh, homegrown jicama from your Washington garden. The crisp, nutty flavor is worth the effort. Happy planting.