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When to Plant Celeriac in Placer County, CA

Placer County, California Zone 9b May

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Avg. last frost April 22
Avg. first frost November 9
Soil temp (4") 72°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Time to start celeriac inside

    These need a head start before your last frost (April 22). 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.

Placer County, California is in USDA Zone 9b. The average last spring frost is April 22 and the first fall frost is November 9, giving you a growing season of approximately 201 days.

At an elevation of 651 feet, Placer County receives approximately 25.3 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Celeriac during the growing season.

Placer County, CA (Zone 9b) Long season
201 days
Last Spring Frost April 22
201 growing days
First Fall Frost November 9

Placer County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🍅 Harvest: Jul 28 – Sep 1
Recommended (50%) ✓ Fits season (61 days to spare)
Start indoors: Mar 25 Transplant: Apr 22 🍅 Harvest: Aug 5 – Sep 9
Safe Start (90%) ✓ Fits season (55 days to spare)
Start indoors: Apr 30 Transplant: May 28 🍅 Harvest: Sep 10 – Oct 15

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 Placer County

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

Soil pH

Your soil pH (6.6–7.2) overlaps with Celeriac's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Celeriac is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (3.1%). 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
0.5″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,377 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 5.2" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 3.9" 1.7" 2.2" 🚿 Regular watering
May 3.9" 0.7" 3.2" 🚿 Regular watering
Jun 3.9" 0.1" 3.8" 🚿 Regular watering
Jul 3.9" 0" 3.9" 🚿 Regular watering
Aug 3.9" 0" 3.9" 🚿 Regular watering
Sep 3.9" 0.2" 3.7" 🚿 Regular watering
Oct 3.9" 1.1" 2.8" 🚿 Regular watering
Nov 3.9" 2.4" 1.5" 💧 Light watering
Dec 4.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Placer 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 ~1,512 GDD — county provides 2,763 GDD Excellent fit

Celeriac Planting Timeline — Placer County, CA

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 1 Apr 1 – Apr 22
Harvest August 5 Aug 5 – Sep 9
Fall Sowing September 14 Sep 14 – Sep 28

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 2-3 times/week

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

201 days in Placer County

Growing Tips for Celeriac in Placer County

Direct sow Celeriac outdoors after April 22 in Placer 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 Placer County, CA?

Placer County is in Zone 9b with an average last frost of April 22. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Placer County, CA?

Placer County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 22 and first fall frost is November 9.

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Your Placer County Garden Planner — Free

A 24-page printable planner built for Placer 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 Placer County, CA. 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.