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When to Plant Jicama in Karnes County, TX

Jicama is a tropical legume grown for its crisp, sweet, starchy root. It requires a very long, warm growing season but produces a refreshing, water chestnut-like tuber.

Karnes County, Texas is in USDA Zone 8b. The average last spring frost is February 26 and the first fall frost is November 30, giving you a growing season of approximately 277 days.

At an elevation of 4,532 feet, Karnes County receives approximately 67.2 inches of rainfall annually with predominantly loam soil. Summer highs average 95ยฐF, so Jicama may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Jicama root diseases.

Karnes County, TX (Zone 8b) Year-round
277 days
Last Spring Frost February 26
277 growing days
First Fall Frost November 30

Karnes County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (71 days to spare)
Start indoors: Dec 27 Transplant: Feb 28 🍅 Harvest: Jul 4 – Sep 12
Recommended (50%) ✓ Fits season (67 days to spare)
Start indoors: Jan 8 Transplant: Mar 12 🍅 Harvest: Jul 16 – Sep 24
Safe Start (90%) ✓ Fits season (63 days to spare)
Start indoors: Feb 2 Transplant: Apr 6 🍅 Harvest: Aug 10 – Oct 19

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 705 gal / 100 sq ft
Jicama needs ~3,188 GDD — county provides 5,907 GDD Excellent fit

Jicama Planting Timeline โ€” Karnes County, TX

Jicama Planting Calendar

Activity When Date Range
Start Indoors January 8 Jan 8 โ€“ Jan 22
Transplant Outdoors March 12 Mar 12 โ€“ Mar 26
Direct Sow March 5 Mar 5 โ€“ Mar 26
Harvest July 16 Jul 16 โ€“ Sep 24

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February โ€”
March Transplant Outdoors Direct Sow
April โ€”
May โ€”
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

120โ€“180 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 8b

Growing Season

277 days

Growing Tips for Karnes County

Start seeds indoors 8-10 weeks before last frost. Pinch off flowers to direct energy to root development. Harvest before first frost when roots are 3-6 inches across.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Level Up Your Garden

Frequently Asked Questions

When should I plant Jicama in Karnes County, TX?

Karnes County is in Zone 8b with an average last frost of February 26. Plan your Jicama planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Karnes County, TX?

Karnes County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is February 26 and first fall frost is November 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Karnes County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Karnes County, TX. Local conditions may vary. Last updated: April 2026.