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When to Plant Lettuce in Union County, PA

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.

Union County, Pennsylvania is in USDA Zone 6a. The average last spring frost is April 27 and the first fall frost is October 22, giving you a growing season of approximately 178 days.

At an elevation of 250 feet, Union County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Lettuce during the growing season.

Union County, PA (Zone 6a) Moderate season
178 days
Last Spring Frost April 27
178 growing days
First Fall Frost October 22

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Aug 6
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 1 – Aug 10
Safe Start (90%) ✓ Fits season (66 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Jun 19 – Aug 28

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 126 gal / 100 sq ft
Lettuce needs ~619 GDD — county provides 2,447 GDD Excellent fit

Lettuce Planting Timeline โ€” Union County, PA

Lettuce Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 โ€“ Apr 6
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Direct Sow April 13 Apr 13 โ€“ May 4
Fall Sowing August 13 Aug 13 โ€“ Aug 27
Harvest June 1 Jun 1 โ€“ Aug 10

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Fall Sowing Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

30โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

178 days

Growing Tips for Union County

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.

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Level Up Your Garden

๐ŸŒพ Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35ยฐF, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Union County, PA?

Union County is in Zone 6a with an average last frost of April 27. Plan your Lettuce planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, PA?

Union County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is April 27 and first fall frost is October 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Union County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Union County, PA. Local conditions may vary. Last updated: April 2026.