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When to Plant Hyssop in Madison County, OH

Madison County, Ohio Zone 6b May

Your May game plan for Madison County, Ohio

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Madison County, Ohio.

Avg. last frost April 22
Avg. first frost October 20
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs

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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.

Madison County, Ohio is in USDA Zone 6b. The average last spring frost is April 22 and the first fall frost is October 20, giving you a growing season of approximately 181 days.

At an elevation of 674 feet, Madison County receives approximately 35.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Hyssop during the growing season.

Madison County, OH (Zone 6b) Moderate season
181 days
Last Spring Frost April 22
181 growing days
First Fall Frost October 20

Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Transplant: Apr 23 🍅 Harvest: Jul 2 – Sep 3
Recommended (50%) ✓ Fits season (41 days to spare)
Transplant: Apr 29 🍅 Harvest: Jul 8 – Sep 9
Safe Start (90%) ✓ Fits season (35 days to spare)
Transplant: May 16 🍅 Harvest: Jul 25 – Sep 26

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 Madison County

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

Soil pH

Your soil pH (5.8–7.1) overlaps with Hyssop's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Hyssop will thrive.

How to Plant Hyssop

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

Succession Planting Hyssop

2
successive plantings in your 181-day season

Sow every 8 weeks. Last sowing by Jul 22 to harvest before frost.

Plant Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.3" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 4.7" 0" ✅ Rainfall sufficient
Jul 2.2" 4.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.9" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.4" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Madison 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 ~1,160 GDD — county provides 2,624 GDD Excellent fit

Hyssop Planting Timeline — Madison County, OH

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors April 29 Apr 29 – May 13
Harvest July 8 Jul 8 – Sep 9

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

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

181 days in Madison County

Growing Tips for Hyssop in Madison County

Direct sow Hyssop outdoors after April 22 in Madison 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 Madison County, OH?

Madison County is in Zone 6b with an average last frost of April 22. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, OH?

Madison County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 22 and first fall frost is October 20.

🌱

Your Madison County Garden Planner — Free

A 24-page printable planner built for Madison 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 Madison County, OH. 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.