When to Plant Horehound in Hardin 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.
Hardin County, Iowa is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.
At an elevation of 507 feet, Hardin County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Horehound to ensure they mature before fall.
Hardin County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Plant Planting Risk Windows
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 Hardin County
How your county's soil matches Horehound's growing requirements.
Soil pH
Your soil pH (5.8–6.9) overlaps with Horehound's range (6.0–8.0), though not a perfect match.
Soil Texture
The silt loam soil in Hardin County is excellent for Horehound — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.1%) — Horehound will thrive.
How to Plant Horehound
Succession Planting Horehound
Sow every 8.6 weeks. Last sowing by Jul 11 to harvest before frost.
Plant Water Budget
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 Planting Timeline — Hardin County, IA
Horehound Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 5 | May 5 – May 19 |
| Harvest | July 21 | Jul 21 – Sep 15 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| 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
75–90 days
🧪 Soil pH
Needs 6–8 · Your soil: acceptable
🗺️ USDA Zone
Zone 4b
📆 Growing Season
164 days in Hardin County
Growing Tips for Horehound in Hardin County
Direct sow Horehound outdoors after April 28 in Hardin 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 →
Horehound in Other Locations
Frequently Asked Questions
When should I plant Horehound in Hardin County, IA?
Hardin County is in Zone 4b with an average last frost of April 28. Plan your Horehound planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hardin County, IA?
Hardin County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 9.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Hardin County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
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