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When to Plant Yam in Willacy County, TX

Willacy County, Texas Zone 10a May

Your May gardening checklist

Your Willacy County, Texas garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost February 4
Avg. first frost December 22
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 13.3 hrs

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True yams are tropical tubers distinct from sweet potatoes, producing large starchy roots that can weigh several pounds. They are a staple food in tropical regions worldwide.

Willacy County, Texas is in USDA Zone 10a. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.

At an elevation of 1,085 feet, Willacy County receives approximately 65.9 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Yam may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Yam root diseases.

Willacy County, TX (Zone 10a) Year-round
321 days
Last Spring Frost February 4
321 growing days
First Fall Frost December 22

Willacy County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (341 days to spare)
Start indoors: Dec 6 Transplant: Jan 24 🍅 Harvest: Jul 25 – Jan 9
Recommended (50%) ✓ Fits season (329 days to spare)
Start indoors: Dec 24 Transplant: Feb 11 🍅 Harvest: Aug 12 – Jan 27
Safe Start (90%) ✓ Fits season (306 days to spare)
Start indoors: Jan 21 Transplant: Mar 11 🍅 Harvest: Sep 9 – Feb 24

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.

Soil Compatibility in Willacy County

How your county's soil matches Yam's growing requirements.

Soil pH

Your soil pH (6.5–7.3) is more alkaline than Yam prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Willacy County is excellent for Yam — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Yam.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Yam.

How to Plant Yam

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,515 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Yam

Yam needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Yam Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 4.3" 2.3" 2" 💧 Light watering
Mar 4.3" 4.4" 0" ✅ Rainfall sufficient
Apr 4.3" 6.4" 0" ✅ Rainfall sufficient
May 4.3" 9.5" 0" ✅ Rainfall sufficient
Jun 4.3" 9.7" 0" ✅ Rainfall sufficient
Jul 4.3" 9" 0" ✅ Rainfall sufficient
Aug 4.3" 8.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.8" 0.5" 💧 Light watering
Nov 4.3" 2.6" 1.7" 💧 Light watering
Dec 4.3" 1.8" 2.5" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Willacy County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Yam Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Yam needs ~6,758 GDD — county provides 8,533 GDD Good fit

Yam Planting Timeline — Willacy County, TX

Yam Planting Calendar

Activity When Date Range
Start Indoors December 24 Dec 24 – Jan 7
Transplant Outdoors February 11 Feb 11 – Feb 25
Direct Sow February 4 Feb 4 – Feb 25
Harvest August 12 Aug 12 – Jan 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

180–330 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 10a

📆 Growing Season

321 days in Willacy County

Growing Tips for Yam in Willacy County

Direct sow Yam outdoors after February 04 in Willacy County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Willacy County, provide afternoon shade for Yam and water deeply in the morning.

Your 322.0-day growing season in Willacy County is tight for Yam (180.0-330.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant tuber pieces in mounds of loose, rich soil. Provide sturdy trellising for climbing vines. Yams require a long, warm growing season of 8-11 months. Harvest when vines die back.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yam in Willacy County, TX?

Willacy County is in Zone 10a with an average last frost of February 4. Plan your Yam planting based on this frost date — see the calendar above for exact timing.

What planting zone is Willacy County, TX?

Willacy County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 4 and first fall frost is December 22.

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Your Willacy County Garden Planner — Free

A 24-page printable planner built for Willacy County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Willacy County, TX. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.