When to Plant Celery in Mercer County, OH
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.
Mercer County, Ohio is in USDA Zone 5b. The average last spring frost is April 25 and the first fall frost is October 17, giving you a growing season of approximately 175 days.
At an elevation of 874 feet, Mercer County receives approximately 32.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Celery to ensure they mature before fall.
Mercer County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
Drainage
Well Drained
Plant Planting Risk Windows
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 Mercer County
How your county's soil matches Celery's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Celery's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Mercer County is excellent for Celery — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Celery will thrive.
How to Plant Celery
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Celery
Sow every 9.1 weeks. Last sowing by Jun 19 to harvest before frost.
For a dedicated fall crop, sow by Aug 08.
Plant Water Budget
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | 5.6" | 3.1" | 2.5" | 💧 Light watering |
| May | 5.6" | 3.8" | 1.8" | 💧 Light watering |
| Jun | 5.6" | 4.1" | 1.5" | 💧 Light watering |
| Jul | 5.6" | 3.6" | 2" | 💧 Light watering |
| Aug | 5.6" | 3.3" | 2.3" | 💧 Light watering |
| Sep | 5.6" | 2.9" | 2.7" | 💧 Light watering |
| Oct | 5.6" | 2.6" | 3" | 🚿 Regular watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Mercer 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 Planting Timeline — Mercer County, OH
Celery Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 11 | Apr 11 – May 2 |
| Harvest | July 18 | Jul 18 – Sep 12 |
| Fall Sowing | August 8 | Aug 8 – Aug 22 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.3"/week · 1-2 times/week
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
175 days in Mercer County
Growing Tips for Celery in Mercer County
Direct sow Celery outdoors after April 25 in Mercer 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
Check more plant combinations with our Companion Planting Checker →
Celery in Other Locations
Frequently Asked Questions
When should I plant Celery in Mercer County, OH?
Mercer County is in Zone 5b with an average last frost of April 25. Plan your Celery planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mercer County, OH?
Mercer County, Ohio is in USDA Hardiness Zone 5b. The average last spring frost is April 25 and first fall frost is October 17.
Plan Your Garden with Confidence
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