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When to Plant Horehound in Granite County, MT

Granite County, Montana Zone 5a May

Granite County, Montana gardeners: here's your May plan

May is a pivotal month for Granite County, Montana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 29
Avg. first frost September 20
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
Looking ahead to June
  • Transplants going out: horehound

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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.

Granite County, Montana is in USDA Zone 5a. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 7,177 feet, Granite County receives approximately 18.9 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Horehound to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Horehound successfully. Mulch heavily to conserve soil moisture.

Granite County, MT (Zone 5a) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20
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Granite County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 25 🍅 Harvest: Aug 10 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: Jun 5 🍅 Harvest: Aug 21 – Oct 16
Safe Start (90%) ✗ May not fit
Transplant: Jun 27 🍅 Harvest: Sep 12 – Nov 7

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 Granite County

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

Soil pH

Your soil pH (6.6–7.6) is within Horehound's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Horehound.

How to Plant Horehound

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

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/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 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" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 2.2" 2.5" 0" ✅ Rainfall sufficient
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 1.5" 0.7" 💧 Light watering
Aug 2.2" 2" 0.2" 💧 Light watering
Sep 2.2" 1.7" 0.5" 💧 Light watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Granite 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 ~887 GDD — county provides 1,225 GDD Excellent fit

Horehound Planting Timeline — Granite County, MT

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors June 5 Jun 5 – Jun 19
Harvest August 21 Aug 21 – Oct 16

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August Harvest
September Harvest
October Harvest
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: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

114 days in Granite County

Growing Tips for Horehound in Granite County

Direct sow Horehound outdoors after May 29 in Granite County when soil has warmed and frost danger has passed.

Granite County receives only 19" of rain annually. Horehound needs consistent moisture — 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 Granite County, MT?

Granite County is in Zone 5a with an average last frost of May 29. Plan your Horehound planting based on this frost date — see the calendar above for exact timing.

What planting zone is Granite County, MT?

Granite County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 29 and first fall frost is September 20.

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Your Granite County Garden Planner — Free

A 24-page printable planner built for Granite 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.

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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 Granite County, MT. 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.