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When to Plant Celeriac in Pima County, AZ

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.

Pima County, Arizona is in USDA Zone 9a. The average last spring frost is April 1 and the first fall frost is November 9, giving you a growing season of approximately 222 days.

At an elevation of 4,327 feet, Pima County receives approximately 14.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103ยฐF, so Celeriac may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Celeriac will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Celeriac successfully. Mulch heavily to conserve soil moisture.

Pima County, AZ (Zone 9a) Long season
222 days
Last Spring Frost April 1
222 growing days
First Fall Frost November 9

Pima County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (85 days to spare)
Start indoors: Feb 22 Transplant: Mar 22 🍅 Harvest: Jul 5 – Aug 9
Recommended (50%) ✓ Fits season (82 days to spare)
Start indoors: Mar 4 Transplant: Apr 1 🍅 Harvest: Jul 15 – Aug 19
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: Apr 7 Transplant: May 5 🍅 Harvest: Aug 18 – Sep 22

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 Pima County

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

Soil pH

Your soil pH (6.8โ€“8.3) is more alkaline than Celeriac prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

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

Organic Matter

Organic matter is low (0.9%). 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 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.3″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 2,128 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” 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 โ€” 0.9" 0" โ„๏ธ Dormant
Feb โ€” 0.8" 0" โ„๏ธ Dormant
Mar โ€” 0.7" 0" โ„๏ธ Dormant
Apr 3.9" 0.5" 3.4" ๐Ÿšฟ Regular watering
May 3.9" 0.4" 3.5" ๐Ÿšฟ Regular watering
Jun 3.9" 0.5" 3.4" ๐Ÿšฟ Regular watering
Jul 3.9" 2.7" 1.2" ๐Ÿ’ง Light watering
Aug 3.9" 3.2" 0.7" ๐Ÿ’ง Light watering
Sep 3.9" 1.9" 2" ๐Ÿšฟ Regular watering
Oct 3.9" 1.4" 2.5" ๐Ÿšฟ Regular watering
Nov 3.9" 0.7" 3.2" ๐Ÿšฟ Regular watering
Dec โ€” 0.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Nov in Pima County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~2,998 GDD — county provides 6,049 GDD Excellent fit

Celeriac Planting Timeline โ€” Pima County, AZ

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 โ€“ Mar 18
Transplant Outdoors April 1 Apr 1 โ€“ Apr 15
Direct Sow March 11 Mar 11 โ€“ Apr 1
Harvest July 15 Jul 15 โ€“ Aug 19
Fall Sowing September 14 Sep 14 โ€“ Sep 28

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.9"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

100โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

222 days in Pima County

Growing Tips for Celeriac in Pima County

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

Sandy soil in Pima County dries quickly โ€” 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 103ยฐF in Pima 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.

Pima County receives only 14" of rain annually. Celeriac needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

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 Pima County, AZ?

Pima County is in Zone 9a with an average last frost of April 1. Plan your Celeriac planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pima County, AZ?

Pima County, Arizona is in USDA Hardiness Zone 9a. The average last spring frost is April 1 and first fall frost is November 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pima County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

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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 Pima County, AZ. Local conditions may vary. Last updated: April 2026.