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When to Plant Celeriac in Irion County, TX

Irion County, Texas Zone 8a May

Your May game plan for Irion County, Texas

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 1
Avg. first frost November 7
Soil temp (4") 68°F
Watering High
Pest pressure Moderate
Daylight 13.6 hrs
  1. Indoor seed-starting week for celeriac

    These need a head start before your last frost (April 1). Sow into cells now so you're ready to transplant in a few weeks.

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Celeriac is a celery relative grown for its knobby, flavorful root rather than its stalks. It has a rich celery flavor and is excellent roasted, mashed, or in soups.

Irion County, Texas is in USDA Zone 8a. The average last spring frost is April 1 and the first fall frost is November 7, giving you a growing season of approximately 220 days.

At an elevation of 1,818 feet, Irion County receives approximately 51.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 100°F, so Celeriac may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Celeriac will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Celeriac root diseases.

Irion County, TX (Zone 8a) Long season
220 days
Last Spring Frost April 1
220 growing days
First Fall Frost November 7

Irion County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.6-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (81 days to spare)
Start indoors: Feb 14 Transplant: Mar 21 🍅 Harvest: Jul 4 – Aug 8
Recommended (50%) ✓ Fits season (80 days to spare)
Start indoors: Feb 25 Transplant: Apr 1 🍅 Harvest: Jul 15 – Aug 19
Safe Start (90%) ✓ Fits season (82 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 29 – Sep 2

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 Irion County

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

Soil pH

Your soil pH (7.6–8.6) is more alkaline than Celeriac prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Irion County warms quickly in spring but drains fast. Celeriac will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.0%). Add 2-3 inches of compost before planting Celeriac.

How to Plant Celeriac

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Celeriac

Celeriac needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Celeriac Needs Rainfall You Supplement Action
Jan 3.8" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 3.9" 1.8" 2.1" 🚿 Regular watering
May 3.9" 1.4" 2.5" 🚿 Regular watering
Jun 3.9" 1.7" 2.2" 🚿 Regular watering
Jul 3.9" 9.5" 0" ✅ Rainfall sufficient
Aug 3.9" 9.5" 0" ✅ Rainfall sufficient
Sep 3.9" 6.8" 0" ✅ Rainfall sufficient
Oct 3.9" 4.5" 0" ✅ Rainfall sufficient
Nov 3.9" 2.8" 1.1" 💧 Light watering
Dec 3.7" 0" ❄️ Dormant

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

Celeriac 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.

Celeriac needs ~2,750 GDD — county provides 5,500 GDD Excellent fit

Celeriac Planting Timeline — Irion County, TX

Celeriac Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors April 1 Apr 1 – Apr 15
Direct Sow March 18 Mar 18 – Apr 8
Harvest July 15 Jul 15 – Aug 19
Fall Sowing August 29 Aug 29 – Sep 12

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

220 days in Irion County

Growing Tips for Celeriac in Irion County

Direct sow Celeriac outdoors after April 01 in Irion County when soil has warmed and frost danger has passed.

Sandy soil in Irion County dries quickly — mulch Celeriac with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 100°F in Irion County, provide afternoon shade for Celeriac and water deeply in the morning.

Common pests for Celeriac in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 10-12 weeks before last frost. Remove side roots as they develop to encourage a single large bulb. Harvest after a light frost for best flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celeriac in Irion County, TX?

Irion County is in Zone 8a with an average last frost of April 1. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Irion County, TX?

Irion County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is April 1 and first fall frost is November 7.

🌱

Your Irion County Garden Planner — Free

A 24-page printable planner built for Irion County (Zone 8a). 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 Irion 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.