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When to Plant Microgreens in Franklin County, PA

Franklin County, Pennsylvania Zone 7a May

Your May game plan for Franklin County, Pennsylvania

Here's what deserves your attention in Franklin County, Pennsylvania this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 16
Avg. first frost October 23
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Start microgreens under lights

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Start harvesting microgreens

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Franklin County, Pennsylvania is in USDA Zone 7a. The average last spring frost is April 16 and the first fall frost is October 23, giving you a growing season of approximately 190 days.

At an elevation of 248 feet, Franklin County receives approximately 41.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Microgreens during the growing season.

Franklin County, PA (Zone 7a) Moderate season
190 days
Last Spring Frost April 16
190 growing days
First Fall Frost October 23
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Franklin County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (154 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: Apr 19 – May 17
Recommended (50%) ✓ Fits season (155 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Apr 23 – May 21
Safe Start (90%) ✓ Fits season (142 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: May 17 – Jun 14

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 Franklin County

How your county's soil matches Microgreens's growing requirements.

Soil pH

Your soil pH (5.0–6.4) is more acidic than Microgreens prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Franklin County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Microgreens.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

37
successive plantings in your 190-day season

Sow every 0.7 weeks. Last sowing by Oct 02 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

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 129 gal / 100 sq ft

Monthly Watering Guide for Microgreens

Microgreens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Microgreens Needs Rainfall You Supplement Action
Jan 3.1" 0" ❄️ Dormant
Feb 2.5" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 3.5" 0.8" 💧 Light watering
Jul 4.3" 4.7" 0" ✅ Rainfall sufficient
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Franklin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Microgreens 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.

Microgreens needs ~256 GDD — county provides 3,467 GDD Excellent fit

Microgreens Planting Timeline — Franklin County, PA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 2 Apr 2 – Apr 23
Harvest April 23 Apr 23 – May 21
Fall Sowing August 14 Aug 14 – Aug 28

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

190 days in Franklin County

Growing Tips for Microgreens in Franklin County

Direct sow Microgreens outdoors after April 16 in Franklin County when soil has warmed and frost danger has passed.

Your generous 190.0-day season in Franklin County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Franklin County, PA?

Franklin County is in Zone 7a with an average last frost of April 16. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Franklin County, PA?

Franklin County, Pennsylvania is in USDA Hardiness Zone 7a. The average last spring frost is April 16 and first fall frost is October 23.

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Your Franklin County Garden Planner — Free

A 24-page printable planner built for Franklin 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.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.