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When to Plant Celeriac in Jefferson County, TX

Jefferson County, Texas Zone 9b May

Your May planting checklist for Jefferson County, Texas

We've pulled the most time-sensitive tasks for Jefferson County, Texas this May and put them front and centre. Tackle them in order.

Avg. last frost February 13
Avg. first frost December 6
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Bring in the celeriac

    If you can't use it all right away, check the food-preservation section of your planner.

Looking ahead to June
  • First harvests: celeriac

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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.

Jefferson County, Texas is in USDA Zone 9b. The average last spring frost is February 13 and the first fall frost is December 6, giving you a growing season of approximately 296 days.

At an elevation of 349 feet, Jefferson County receives approximately 64.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 101°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.

Jefferson County, TX (Zone 9b) Year-round
296 days
Last Spring Frost February 13
296 growing days
First Fall Frost December 6
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Jefferson County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (168 days to spare)
Start indoors: Dec 27 Transplant: Jan 24 🍅 Harvest: May 9 – Jun 13
Recommended (50%) ✓ Fits season (156 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: May 29 – Jul 3
Safe Start (90%) ✓ Fits season (153 days to spare)
Start indoors: Feb 6 Transplant: Mar 6 🍅 Harvest: Jun 19 – Jul 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 Jefferson County

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

Soil pH

Your soil pH (5.4–6.5) is more acidic than Celeriac prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Jefferson 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 moderate (2.2%). Annual compost additions will help Celeriac.

How to Plant Celeriac

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

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

Water stress score is 6/10 — 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 1.6" 0" ❄️ Dormant
Feb 3.9" 2.1" 1.8" 💧 Light watering
Mar 3.9" 4.4" 0" ✅ Rainfall sufficient
Apr 3.9" 6.3" 0" ✅ Rainfall sufficient
May 3.9" 9.8" 0" ✅ Rainfall sufficient
Jun 3.9" 10.7" 0" ✅ Rainfall sufficient
Jul 3.9" 8.8" 0" ✅ Rainfall sufficient
Aug 3.9" 6.6" 0" ✅ Rainfall sufficient
Sep 3.9" 6.6" 0" ✅ Rainfall sufficient
Oct 3.9" 4.4" 0" ✅ Rainfall sufficient
Nov 3.9" 2.1" 1.8" 💧 Light watering
Dec 3.9" 1.6" 2.3" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Jefferson 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 ~2,832 GDD — county provides 7,647 GDD Excellent fit

Celeriac Planting Timeline — Jefferson County, TX

Celeriac Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 – Jan 30
Transplant Outdoors February 13 Feb 13 – Feb 27
Direct Sow January 23 Jan 23 – Feb 13
Harvest May 29 May 29 – Jul 3
Fall Sowing October 11 Oct 11 – Oct 25

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 9b

📆 Growing Season

296 days in Jefferson County

Growing Tips for Celeriac in Jefferson County

Direct sow Celeriac outdoors after February 13 in Jefferson County when soil has warmed and frost danger has passed.

Sandy soil in Jefferson 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 101°F in Jefferson 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 Jefferson County, TX?

Jefferson County is in Zone 9b with an average last frost of February 13. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, TX?

Jefferson County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 13 and first fall frost is December 6.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 9b). 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 Jefferson 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.