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When to Plant Celery in Washington County, MD

Washington County, Maryland Zone 6b April

Top priorities for Washington County, Maryland gardeners in April

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Washington County, Maryland.

Avg. last frost April 16
Avg. first frost October 23
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 13.1 hrs
  1. Harden off and plant celery

    Frost risk is low now in Washington County, Maryland. If you've been covering beds overnight, you can stop.

  2. Scatter celery into prepared beds

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

Get ahead of May
  • Starting indoors: celery

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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.

Washington County, Maryland is in USDA Zone 6b. The average last spring frost is April 16 and the first fall frost is October 23, giving you a growing season of approximately 190 days.

At an elevation of 1,022 feet, Washington County receives approximately 45.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Celery during the growing season.

Washington County, MD (Zone 6b) Moderate season
190 days
Last Spring Frost April 16
190 growing days
First Fall Frost October 23
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Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: Jul 5 – Aug 30
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jul 9 – Sep 3
Safe Start (90%) ✓ Fits season (37 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Aug 2 – Sep 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 Washington County

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

Soil pH

Your soil pH (5.4–6.8) overlaps with Celery's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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

2
successive plantings in your 190-day season

Sow every 9.1 weeks. Last sowing by Jun 25 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 490 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 3.1" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 5.6" 4" 1.6" 💧 Light watering
May 5.6" 3.9" 1.7" 💧 Light watering
Jun 5.6" 4" 1.6" 💧 Light watering
Jul 5.6" 5.1" 0.5" 💧 Light watering
Aug 5.6" 4.5" 1.1" 💧 Light watering
Sep 5.6" 3.4" 2.2" 💧 Light watering
Oct 5.6" 3.6" 2" 💧 Light watering
Nov 4" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Washington County). Supplement amounts are based on average rainfall — 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" — 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.

Celery needs ~1,375 GDD — county provides 2,612 GDD Excellent fit

Celery Planting Timeline — Washington County, MD

Celery Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 2 Apr 2 – Apr 23
Harvest July 9 Jul 9 – Sep 3
Fall Sowing August 14 Aug 14 – Aug 28

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

190 days in Washington County

Growing Tips for Celery in Washington County

Direct sow Celery outdoors after April 16 in Washington 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 Washington County, MD?

Washington County is in Zone 6b with an average last frost of April 16. Plan your Celery planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, MD?

Washington County, Maryland is in USDA Hardiness Zone 6b. The average last spring frost is April 16 and first fall frost is October 23.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington County (Zone 6b). 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 Washington County, MD. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.