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When to Plant Celery in Middlesex County, NJ

Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.

Middlesex County, New Jersey is in USDA Zone 7a. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.

At an elevation of 947 feet, Middlesex County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94ยฐF, providing good warmth for Celery during the growing season.

Middlesex County, NJ (Zone 7a) Long season
228 days
Last Spring Frost March 29
228 growing days
First Fall Frost November 12

Middlesex County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (88 days to spare)
Start indoors: Feb 18 Transplant: Mar 25 🍅 Harvest: Jun 17 – Aug 12
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Feb 22 Transplant: Mar 29 🍅 Harvest: Jun 21 – Aug 16
Safe Start (90%) ✓ Fits season (97 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jul 2 – Aug 27

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 Middlesex County

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

Soil pH

Your soil pH (5.0โ€“6.6) is more acidic than Celery prefers (6.0โ€“7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Middlesex County is excellent for Celery โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Celery.

How to Plant Celery

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

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

Succession Planting Celery

3
successive plantings in your 228-day season

Sow every 9.1 weeks. Last sowing by Jul 15 to harvest before frost.

For a dedicated fall crop, sow by Sep 03.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 937 gal / 100 sq ft

Monthly Watering Guide for Celery

Celery needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Celery Needs Rainfall You Supplement Action
Jan โ€” 3.3" 0" โ„๏ธ Dormant
Feb โ€” 3.1" 0" โ„๏ธ Dormant
Mar 5.6" 3.6" 2" ๐Ÿ’ง Light watering
Apr 5.6" 4.2" 1.4" ๐Ÿ’ง Light watering
May 5.6" 4.8" 0.8" ๐Ÿ’ง Light watering
Jun 5.6" 4.9" 0.7" ๐Ÿ’ง Light watering
Jul 5.6" 4" 1.6" ๐Ÿ’ง Light watering
Aug 5.6" 4.3" 1.3" ๐Ÿ’ง Light watering
Sep 5.6" 3.4" 2.2" ๐Ÿ’ง Light watering
Oct 5.6" 3.7" 1.9" ๐Ÿ’ง Light watering
Nov 5.6" 3.2" 2.4" ๐Ÿ’ง Light watering
Dec โ€” 3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Middlesex County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Celery 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.

Celery needs ~2,050 GDD — county provides 4,674 GDD Excellent fit

Celery Planting Timeline โ€” Middlesex County, NJ

Celery Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 โ€“ Mar 8
Transplant Outdoors March 29 Mar 29 โ€“ Apr 12
Direct Sow March 15 Mar 15 โ€“ Apr 5
Harvest June 21 Jun 21 โ€“ Aug 16
Fall Sowing September 3 Sep 3 โ€“ Sep 17

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
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

1.3"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 7a

๐Ÿ“† Growing Season

228 days in Middlesex County

Growing Tips for Celery in Middlesex County

Direct sow Celery outdoors after March 29 in Middlesex County when soil has warmed and frost danger has passed.

Common pests for Celery 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. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder 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 Celery in Middlesex County, NJ?

Middlesex County is in Zone 7a with an average last frost of March 29. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Middlesex County, NJ?

Middlesex County, New Jersey is in USDA Hardiness Zone 7a. The average last spring frost is March 29 and first fall frost is November 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Middlesex County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Middlesex County, NJ. Local conditions may vary. Last updated: April 2026.