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When to Plant Horehound in Elmore County, ID

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

Elmore County, Idaho is in USDA Zone 6a. The average last spring frost is April 27 and the first fall frost is October 14, giving you a growing season of approximately 170 days.

At an elevation of 5,944 feet, Elmore County receives approximately 20.3 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Horehound during the growing season.

Elmore County, ID (Zone 6a) Moderate season
170 days
Last Spring Frost April 27
170 growing days
First Fall Frost October 14

Elmore County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (36 days to spare)
Transplant: Apr 21 🍅 Harvest: Jul 7 – Sep 1
Recommended (50%) ✓ Fits season (30 days to spare)
Transplant: May 4 🍅 Harvest: Jul 20 – Sep 14
Safe Start (90%) ✓ Fits season (29 days to spare)
Transplant: May 26 🍅 Harvest: Aug 11 – Oct 6

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 Elmore County

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

Soil pH

Your soil pH (6.7โ€“8.3) overlaps with Horehound's range (6.0โ€“8.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Horehound.

Organic Matter

Organic matter is moderate (2.7%). 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 170-day season

Sow every 8.6 weeks. Last sowing by Jul 16 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 270 gal / 100 sq ft
Drought risk

Water stress score is 8/10 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€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.3" 0" โ„๏ธ Dormant
Mar โ€” 1.7" 0" โ„๏ธ Dormant
Apr 2.2" 1.9" 0.3" ๐Ÿ’ง Light watering
May 2.2" 2.7" 0" โœ… Rainfall sufficient
Jun 2.2" 1.6" 0.6" ๐Ÿ’ง Light watering
Jul 2.2" 1.6" 0.6" ๐Ÿ’ง Light watering
Aug 2.2" 1.9" 0.3" ๐Ÿ’ง Light watering
Sep 2.2" 1.6" 0.6" ๐Ÿ’ง Light watering
Oct 2.2" 1.7" 0.5" ๐Ÿ’ง Light watering
Nov โ€” 1.4" 0" โ„๏ธ Dormant
Dec โ€” 1.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Elmore 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 ~1,320 GDD — county provides 2,720 GDD Excellent fit

Horehound Planting Timeline โ€” Elmore County, ID

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors May 4 May 4 โ€“ May 18
Harvest July 20 Jul 20 โ€“ Sep 14

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 Only during dry spells

๐Ÿ“… Days to Maturity

75โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“8 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

170 days in Elmore County

Growing Tips for Horehound in Elmore County

Direct sow Horehound outdoors after April 27 in Elmore County when soil has warmed and frost danger has passed.

Elmore County receives only 20" of rain annually. Horehound needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

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 Elmore County, ID?

Elmore County is in Zone 6a with an average last frost of April 27. Plan your Horehound planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Elmore County, ID?

Elmore County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is April 27 and first fall frost is October 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Elmore County gardeners in Zone 6a 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 Elmore County, ID. Local conditions may vary. Last updated: April 2026.