When to Plant Celery in Coos County, NH
May in Coos County, New Hampshire — your action list
Your garden in Coos County, New Hampshire is working on a schedule, even when you're not. Here's where you should be this May.
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Set out celery seedlings
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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Plant celery from seed, right in the garden
Mark the row. Birds and stray feet both have opinions about unmarked beds.
Coming up in June — start thinking about
- Starting indoors: celery
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.
Coos County, New Hampshire is in USDA Zone 4b. The average last spring frost is May 18 and the first fall frost is September 30, giving you a growing season of approximately 135 days.
At an elevation of 604 feet, Coos County receives approximately 40.7 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.
Coos County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.6
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 Coos County
How your county's soil matches Celery's growing requirements.
Soil pH
Your soil pH (5.2–6.6) is more acidic than Celery prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Coos 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 12 weeks before your first frost date for a fall harvest.
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 | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 2.9" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | — | 3.4" | 0" | ❄️ Dormant |
| May | 5.6" | 3.6" | 2" | 💧 Light watering |
| Jun | 5.6" | 3.5" | 2.1" | 💧 Light watering |
| Jul | 5.6" | 3.9" | 1.7" | 💧 Light watering |
| Aug | 5.6" | 4" | 1.6" | 💧 Light watering |
| Sep | 5.6" | 3.7" | 1.9" | 💧 Light watering |
| Oct | — | 3.1" | 0" | ❄️ Dormant |
| Nov | — | 3.1" | 0" | ❄️ Dormant |
| Dec | — | 3.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Coos 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 — Coos County, NH
Celery Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 6 | Apr 6 – Apr 20 |
| Transplant Outdoors | May 18 | May 18 – Jun 1 |
| Direct Sow | May 11 | May 11 – Jun 1 |
| Harvest | August 10 | Aug 10 – Oct 5 |
| Fall Sowing | July 8 | Jul 8 – Jul 22 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| 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 4b
📆 Growing Season
135 days in Coos County
Growing Tips for Celery in Coos County
Direct sow Celery outdoors after May 18 in Coos 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 Coos County, NH?
Coos County is in Zone 4b with an average last frost of May 18. Plan your Celery planting based on this frost date — see the calendar above for exact timing.
What planting zone is Coos County, NH?
Coos County, New Hampshire is in USDA Hardiness Zone 4b. The average last spring frost is May 18 and first fall frost is September 30.
Your Coos County Garden Planner — Free
A 24-page printable planner built for Coos County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.