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When to Plant Yam in Zavala County, TX

Zavala County, Texas Zone 9a May

Zavala County, Texas gardeners: here's your May plan

Here's what deserves your attention in Zavala County, Texas this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost February 26
Avg. first frost November 29
Soil temp (4") 60°F
Watering Low
Pest pressure High
Daylight 13.4 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.

Zavala County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 29, giving you a growing season of approximately 276 days.

At an elevation of 4,905 feet, Zavala County receives approximately 59.7 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Yam during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Yam root diseases.

Zavala County, TX (Zone 9a) Year-round
276 days
Last Spring Frost February 26
276 growing days
First Fall Frost November 29
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Zavala County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Jan 1 Transplant: Feb 19 🍅 Harvest: Aug 20 – Dec 17
Recommended (50%) ✗ May not fit
Start indoors: Jan 15 Transplant: Mar 5 🍅 Harvest: Sep 3 – Dec 31
Safe Start (90%) ✓ Fits season (325 days to spare)
Start indoors: Feb 9 Transplant: Mar 30 🍅 Harvest: Sep 28 – Jan 25

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 Zavala County

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

Soil pH

Your soil pH (6.4–7.4) is more alkaline than Yam prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting 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
0.1″/week
Watering frequency Only during dry spells
Season total 234 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 4.3" 1.9" 2.4" 🚿 Regular watering
Mar 4.3" 3.2" 1.1" 💧 Light watering
Apr 4.3" 6.7" 0" ✅ Rainfall sufficient
May 4.3" 8.7" 0" ✅ Rainfall sufficient
Jun 4.3" 10.5" 0" ✅ Rainfall sufficient
Jul 4.3" 6.5" 0" ✅ Rainfall sufficient
Aug 4.3" 7.8" 0" ✅ Rainfall sufficient
Sep 4.3" 5.9" 0" ✅ Rainfall sufficient
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Zavala 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 ~5,036 GDD — county provides 5,470 GDD Good fit

Yam Planting Timeline — Zavala County, TX

Yam Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow February 26 Feb 26 – Mar 19
Harvest September 3 Sep 3 – Dec 31

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

180–330 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

276 days in Zavala County

Growing Tips for Yam in Zavala County

Direct sow Yam outdoors after February 26 in Zavala County when soil has warmed and frost danger has passed.

Your 277.0-day growing season in Zavala 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 Zavala County, TX?

Zavala County is in Zone 9a with an average last frost of February 26. Plan your Yam planting based on this frost date — see the calendar above for exact timing.

What planting zone is Zavala County, TX?

Zavala County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is November 29.

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Your Zavala County Garden Planner — Free

A 24-page printable planner built for Zavala County (Zone 9a). 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 Zavala 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.