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When to Plant Blackberries in Lehigh County, PA

Lehigh County, Pennsylvania Zone 7a May

May in Lehigh County, Pennsylvania — your action list

Each item below is timed to Lehigh County, Pennsylvania's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 20
Avg. first frost October 24
Soil temp (4") 62°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Get blackberries in the ground

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

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Blackberries are vigorous bramble fruits that produce sweet-tart berries on thorny or thornless canes. They are prolific producers and relatively low-maintenance once established.

Lehigh County, Pennsylvania is in USDA Zone 7a. The average last spring frost is April 20 and the first fall frost is October 24, giving you a growing season of approximately 187 days.

At an elevation of 376 feet, Lehigh County receives approximately 44.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Blackberries during the growing season.

Lehigh County, PA (Zone 7a) Moderate season
187 days
Last Spring Frost April 20
187 growing days
First Fall Frost October 24
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Lehigh County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 4
Recommended (50%) ✓ Fits season
Transplant: May 11
Safe Start (90%) ✓ Fits season
Transplant: May 31

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 Lehigh County

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

Soil pH

Your soil pH (5.2–6.2) overlaps with Blackberries's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Blackberries.

Organic Matter

Organic matter is moderate (4.0%). Annual compost additions will help Blackberries.

How to Plant Blackberries

24"
Between Plants
72"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Blackberries

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

Month Blackberries Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 3.2" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 4.3" 4.3" 0" ✅ Rainfall sufficient
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.7" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 3.1" 0" ❄️ Dormant

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

Blackberries 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.

Blackberries needs ~9,171 GDD — county provides 3,132 GDD May not mature

Blackberries Planting Timeline — Lehigh County, PA

Blackberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 11 May 11 – May 25

· 24" apart · Rows 72" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

187 days in Lehigh County

Growing Tips for Blackberries in Lehigh County

Direct sow Blackberries outdoors after April 20 in Lehigh County when soil has warmed and frost danger has passed.

Your 187.0-day growing season in Lehigh County is tight for Blackberries (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant bare-root canes in spring. Provide a sturdy trellis system. Prune out spent fruiting canes after harvest. New canes fruit in their second year (floricanes).

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Blackberries in Lehigh County, PA?

Lehigh County is in Zone 7a with an average last frost of April 20. Plan your Blackberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lehigh County, PA?

Lehigh County, Pennsylvania is in USDA Hardiness Zone 7a. The average last spring frost is April 20 and first fall frost is October 24.

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Your Lehigh County Garden Planner — Free

A 24-page printable planner built for Lehigh 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 Lehigh 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.