When to Plant Collard Greens in Northumberland County, PA
Top priorities for Northumberland County, Pennsylvania gardeners in May
We've pulled the most time-sensitive tasks for Northumberland County, Pennsylvania this May and put them front and centre. Tackle them in order.
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Get collard greens seeds going inside
You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.
Coming up in June — start thinking about
- First harvests: collard greens
Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.
Northumberland County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 17 and the first fall frost is October 26, giving you a growing season of approximately 192 days.
At an elevation of 324 feet, Northumberland County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Collard Greens during the growing season.
Northumberland County Soil Profile
Soil Type
Silt Loam
Soil pH
5.1-6.6
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 Northumberland County
How your county's soil matches Collard Greens's growing requirements.
Soil pH
Your soil pH (5.1–6.6) is more acidic than Collard Greens prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Northumberland County is excellent for Collard Greens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.4%). Annual compost additions will help Collard Greens.
How to Plant Collard Greens
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Collard Greens
Sow every 6.3 weeks. Last sowing by Aug 12 to harvest before frost.
For a dedicated fall crop, sow by Aug 17.
Plant Water Budget
Monthly Watering Guide for Collard Greens
Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Collard Greens Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 2.8" | 0" | ❄️ Dormant |
| Mar | — | 3.4" | 0" | ❄️ Dormant |
| Apr | 3.5" | 3.2" | 0.3" | 💧 Light watering |
| May | 3.5" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 3.8" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 3.4" | 0.1" | 💧 Light watering |
| Sep | 3.5" | 3.3" | 0.2" | 💧 Light watering |
| Oct | 3.5" | 3.8" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 3.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Northumberland County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Collard Greens 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.
Collard Greens Planting Timeline — Northumberland County, PA
Collard Greens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 13 | Mar 13 – Mar 27 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Direct Sow | April 3 | Apr 3 – Apr 24 |
| Harvest | June 12 | Jun 12 – Aug 14 |
| Fall Sowing | August 17 | Aug 17 – Aug 31 |
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 | Harvest |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Natural rainfall sufficient
📅 Days to Maturity
55–75 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
192 days in Northumberland County
Growing Tips for Collard Greens in Northumberland County
Direct sow Collard Greens outdoors after April 17 in Northumberland County when soil has warmed and frost danger has passed.
Common pests for Collard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Collard Greens in Other Locations
Frequently Asked Questions
When should I plant Collard Greens in Northumberland County, PA?
Northumberland County is in Zone 6b with an average last frost of April 17. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Northumberland County, PA?
Northumberland County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 17 and first fall frost is October 26.
Your Northumberland County Garden Planner — Free
A 24-page printable planner built for Northumberland 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.