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When to Plant Horehound in Allamakee County, IA

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

Allamakee County, Iowa is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 804 feet, Allamakee County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Horehound to ensure they mature before fall.

Allamakee County, IA (Zone 4b) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Allamakee County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Transplant: May 1 🍅 Harvest: Jul 17 – Sep 11
Recommended (50%) ✓ Fits season (18 days to spare)
Transplant: May 9 🍅 Harvest: Jul 25 – Sep 19
Safe Start (90%) ✓ Fits season (17 days to spare)
Transplant: May 22 🍅 Harvest: Aug 7 – Oct 2

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 Allamakee County

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

Soil pH

Your soil pH (5.9โ€“7.1) overlaps with Horehound's range (6.0โ€“8.0), though not a perfect match.

Soil Texture

The silt loam soil in Allamakee County is excellent for Horehound โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.7%) โ€” Horehound will thrive.

How to Plant Horehound

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

Succession Planting Horehound

2
successive plantings in your 158-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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.9" 0" โ„๏ธ Dormant
Mar โ€” 2.7" 0" โ„๏ธ Dormant
Apr โ€” 4" 0" โ„๏ธ Dormant
May 2.2" 4.3" 0" โœ… Rainfall sufficient
Jun 2.2" 5.3" 0" โœ… Rainfall sufficient
Jul 2.2" 4.6" 0" โœ… Rainfall sufficient
Aug 2.2" 4.2" 0" โœ… Rainfall sufficient
Sep 2.2" 3.4" 0" โœ… Rainfall sufficient
Oct 2.2" 2.9" 0" โœ… Rainfall sufficient
Nov โ€” 3" 0" โ„๏ธ Dormant
Dec โ€” 2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Allamakee County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 1,817 GDD Excellent fit

Horehound Planting Timeline โ€” Allamakee County, IA

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors May 9 May 9 โ€“ May 23
Harvest July 25 Jul 25 โ€“ Sep 19

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

75โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“8 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

158 days in Allamakee County

Growing Tips for Horehound in Allamakee County

Direct sow Horehound outdoors after May 02 in Allamakee 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 Allamakee County, IA?

Allamakee County is in Zone 4b with an average last frost of May 2. Plan your Horehound planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Allamakee County, IA?

Allamakee County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Allamakee County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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