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When to Plant Celeriac in Northumberland County, VA

Northumberland County, Virginia Zone 8a May

Your May gardening checklist

A quick May briefing for Northumberland County, Virginia gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 5
Avg. first frost November 4
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 14 hrs
  1. Indoor seed-starting week for celeriac

    These need a head start before your last frost (April 5). 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.

Northumberland County, Virginia is in USDA Zone 8a. The average last spring frost is April 5 and the first fall frost is November 4, giving you a growing season of approximately 213 days.

At an elevation of 207 feet, Northumberland County receives approximately 54.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Celeriac during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Celeriac root diseases.

Northumberland County, VA (Zone 8a) Long season
213 days
Last Spring Frost April 5
213 growing days
First Fall Frost November 4

Northumberland County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: Jul 11 – Aug 15
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: Jul 19 – Aug 23
Safe Start (90%) ✓ Fits season (86 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Aug 9 – Sep 13

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 Northumberland County

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

Soil pH

Your soil pH (5.4–7.1) overlaps with Celeriac's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Northumberland County is excellent for Celeriac — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help 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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 4.4" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 5.2" 0" ❄️ Dormant
Apr 3.9" 4.2" 0" ✅ Rainfall sufficient
May 3.9" 4.5" 0" ✅ Rainfall sufficient
Jun 3.9" 5.5" 0" ✅ Rainfall sufficient
Jul 3.9" 6.5" 0" ✅ Rainfall sufficient
Aug 3.9" 5.3" 0" ✅ Rainfall sufficient
Sep 3.9" 3.7" 0.2" 💧 Light watering
Oct 3.9" 4" 0" ✅ Rainfall sufficient
Nov 3.9" 3.7" 0.2" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Northumberland 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 ~2,090 GDD — county provides 4,047 GDD Excellent fit

Celeriac Planting Timeline — Northumberland County, VA

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors April 5 Apr 5 – Apr 19
Direct Sow March 22 Mar 22 – Apr 12
Harvest July 19 Jul 19 – Aug 23
Fall Sowing August 26 Aug 26 – Sep 9

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

Month-by-Month Timeline

MonthActivities
January
February
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: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

213 days in Northumberland County

Growing Tips for Celeriac in Northumberland County

Direct sow Celeriac outdoors after April 05 in Northumberland County when soil has warmed and frost danger has passed.

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 Northumberland County, VA?

Northumberland County is in Zone 8a with an average last frost of April 5. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Northumberland County, VA?

Northumberland County, Virginia is in USDA Hardiness Zone 8a. The average last spring frost is April 5 and first fall frost is November 4.

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Your Northumberland County Garden Planner — Free

A 24-page printable planner built for Northumberland 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 Northumberland County, VA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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