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When to Plant Horehound in Iowa County, WI

Iowa County, Wisconsin Zone 5a May

Iowa County, Wisconsin gardeners: here's your May plan

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 May 3
Avg. first frost October 7
Soil temp (4") 53°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Move horehound from tray to bed

    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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Horehound is a woolly, drought-tolerant perennial herb traditionally used for cough remedies and candy. It has a distinctive bitter, menthol-like flavor.

Iowa County, Wisconsin is in USDA Zone 5a. The average last spring frost is May 3 and the first fall frost is October 7, giving you a growing season of approximately 157 days.

At an elevation of 602 feet, Iowa County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Horehound to ensure they mature before fall.

Iowa County, WI (Zone 5a) Moderate season
157 days
Last Spring Frost May 3
157 growing days
First Fall Frost October 7
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Iowa 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 (18 days to spare)
Transplant: May 4 🍅 Harvest: Jul 20 – Sep 14
Recommended (50%) ✓ Fits season (17 days to spare)
Transplant: May 10 🍅 Harvest: Jul 26 – Sep 20
Safe Start (90%) ✓ Fits season (8 days to spare)
Transplant: May 28 🍅 Harvest: Aug 13 – Oct 8

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 Iowa County

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

Soil pH

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

Soil Texture

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

Organic Matter

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

How to Plant Horehound

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

Succession Planting Horehound

2
successive plantings in your 157-day season

Sow every 8.6 weeks. Last sowing by Jul 09 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Horehound

Horehound 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 Horehound Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 3.7" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.5" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

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

Horehound 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.

Horehound needs ~949 GDD — county provides 1,805 GDD Excellent fit

Horehound Planting Timeline — Iowa County, WI

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors May 10 May 10 – May 24
Harvest July 26 Jul 26 – Sep 20

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

75–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

157 days in Iowa County

Growing Tips for Horehound in Iowa County

Direct sow Horehound outdoors after May 03 in Iowa County when soil has warmed and frost danger has passed.

General growing tips

Direct sow or start from divisions. Thrives in poor, dry soil. Harvest stems just before flowering. Deadhead to prevent aggressive self-seeding. Very drought-tolerant once established.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Horehound in Iowa County, WI?

Iowa County is in Zone 5a with an average last frost of May 3. Plan your Horehound planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iowa County, WI?

Iowa County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 7.

🌱

Your Iowa County Garden Planner — Free

A 24-page printable planner built for Iowa County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Iowa County, WI. 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.