When to Plant Celery in Northampton County, PA
What to do in May
Your garden in Northampton County, Pennsylvania is working on a schedule, even when you're not. Here's where you should be this May.
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Get celery seeds going inside
These need a head start before your last frost (April 20). Sow into cells now so you're ready to transplant in a few weeks.
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.
Northampton County, Pennsylvania is in USDA Zone 7a. The average last spring frost is April 20 and the first fall frost is October 24, giving you a growing season of approximately 187 days.
At an elevation of 354 feet, Northampton County receives approximately 49.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Celery during the growing season.
Northampton County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.7
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 Northampton County
How your county's soil matches Celery's growing requirements.
Soil pH
Your soil pH (4.9–6.7) is more acidic than Celery prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Northampton County is excellent for Celery — 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
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 26 to harvest before frost.
For a dedicated fall crop, sow by Aug 15.
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 | — | 3.4" | 0" | ❄️ Dormant |
| Feb | — | 3.6" | 0" | ❄️ Dormant |
| Mar | — | 4.6" | 0" | ❄️ Dormant |
| Apr | 5.6" | 4.3" | 1.3" | 💧 Light watering |
| May | 5.6" | 3.9" | 1.7" | 💧 Light watering |
| Jun | 5.6" | 5.1" | 0.5" | 💧 Light watering |
| Jul | 5.6" | 4.5" | 1.1" | 💧 Light watering |
| Aug | 5.6" | 4.7" | 0.9" | 💧 Light watering |
| Sep | 5.6" | 4.1" | 1.5" | 💧 Light watering |
| Oct | 5.6" | 4.1" | 1.5" | 💧 Light watering |
| Nov | — | 3.6" | 0" | ❄️ Dormant |
| Dec | — | 3.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Northampton 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 — Northampton County, PA
Celery Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | April 20 | Apr 20 – May 4 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Harvest | July 13 | Jul 13 – Sep 7 |
| Fall Sowing | August 15 | Aug 15 – Aug 29 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
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: too_acidic
🗺️ USDA Zone
Zone 7a
📆 Growing Season
187 days in Northampton County
Growing Tips for Celery in Northampton County
Direct sow Celery outdoors after April 20 in Northampton 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 Northampton County, PA?
Northampton County is in Zone 7a with an average last frost of April 20. Plan your Celery planting based on this frost date — see the calendar above for exact timing.
What planting zone is Northampton County, PA?
Northampton County, Pennsylvania is in USDA Hardiness Zone 7a. The average last spring frost is April 20 and first fall frost is October 24.
Your Northampton County Garden Planner — Free
A 24-page printable planner built for Northampton County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.