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When to Plant Hyssop in Luzerne County, PA

Luzerne County, Pennsylvania Zone 6b May

What to do in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 28
Avg. first frost October 17
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Transplant hyssop outside

    Frost risk is low now in Luzerne County, Pennsylvania. If you've been covering beds overnight, you can stop.

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Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.

Luzerne County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 28 and the first fall frost is October 17, giving you a growing season of approximately 172 days.

At an elevation of 701 feet, Luzerne County receives approximately 44.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Hyssop during the growing season.

Luzerne County, PA (Zone 6b) Moderate season
172 days
Last Spring Frost April 28
172 growing days
First Fall Frost October 17
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Luzerne County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Transplant: Apr 29 🍅 Harvest: Jul 8 – Sep 9
Recommended (50%) ✓ Fits season (32 days to spare)
Transplant: May 5 🍅 Harvest: Jul 14 – Sep 15
Safe Start (90%) ✓ Fits season (32 days to spare)
Transplant: May 21 🍅 Harvest: Jul 30 – Oct 1

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 Luzerne County

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

Soil pH

Your soil pH (5.2–6.3) is more acidic than Hyssop prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Hyssop prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Hyssop.

How to Plant Hyssop

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Hyssop

2
successive plantings in your 172-day season

Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Hyssop

Hyssop needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Hyssop Needs Rainfall You Supplement Action
Jan 3.4" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 2.2" 4.1" 0" ✅ Rainfall sufficient
May 2.2" 4.2" 0" ✅ Rainfall sufficient
Jun 2.2" 3.7" 0" ✅ Rainfall sufficient
Jul 2.2" 4.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3.8" 0" ✅ Rainfall sufficient
Sep 2.2" 3.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3.6" 0" ✅ Rainfall sufficient
Nov 3.6" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

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

Hyssop 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.

Hyssop needs ~1,220 GDD — county provides 2,623 GDD Excellent fit

Hyssop Planting Timeline — Luzerne County, PA

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors May 5 May 5 – May 19
Harvest July 14 Jul 14 – Sep 15

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

172 days in Luzerne County

Growing Tips for Hyssop in Luzerne County

Direct sow Hyssop outdoors after April 28 in Luzerne County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.

Companion Planting

Good Companions

Avoid Planting Near

  • Radish

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyssop in Luzerne County, PA?

Luzerne County is in Zone 6b with an average last frost of April 28. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Luzerne County, PA?

Luzerne County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 28 and first fall frost is October 17.

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Your Luzerne County Garden Planner — Free

A 24-page printable planner built for Luzerne 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.

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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 Luzerne 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.