When to Plant Lettuce in Northumberland County, PA
Your May gardening checklist
Your garden in Northumberland County, Pennsylvania is working on a schedule, even when you're not. Here's where you should be this May.
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Sow lettuce in trays indoors
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
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It's harvest week for lettuce
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
A few tasks this May that'll pay off in June
- First harvests: lettuce
Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.
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 Lettuce 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 Lettuce's growing requirements.
Soil pH
Your soil pH (5.1–6.6) is more acidic than Lettuce prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Northumberland County is excellent for Lettuce — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.4%). Annual compost additions will help Lettuce.
How to Plant Lettuce
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Lettuce
Sow every 3.4 weeks. Last sowing by Aug 27 to harvest before frost.
For a dedicated fall crop, sow by Aug 17.
Plant Water Budget
Monthly Watering Guide for Lettuce
Lettuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Lettuce Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 2.8" | 0" | ❄️ Dormant |
| Mar | — | 3.4" | 0" | ❄️ Dormant |
| Apr | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| May | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 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.
Lettuce 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.
Lettuce Planting Timeline — Northumberland County, PA
Lettuce 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 | May 22 | May 22 – Jul 31 |
| Fall Sowing | August 17 | Aug 17 – Aug 31 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
30–60 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
192 days in Northumberland County
Growing Tips for Lettuce in Northumberland County
Direct sow Lettuce outdoors after April 17 in Northumberland County when soil has warmed and frost danger has passed.
Summer highs in Northumberland County reach 91°F — grow Lettuce as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 192.0-day season in Northumberland County allows multiple plantings of Lettuce. Sow every 15.0 days for continuous harvest.
Common pests for Lettuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.
Recommended Lettuce Varieties for Northumberland County
Bolt-resistant varieties for warm summers — grow as spring/fall crop
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Very easy to save. Let a few plants bolt each season.
Lettuce in Other Locations
Frequently Asked Questions
When should I plant Lettuce in Northumberland County, PA?
Northumberland County is in Zone 6b with an average last frost of April 17. Plan your Lettuce 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.