Blog

When to Plant Horehound in Calgary, AB

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

Calgary, Alberta is in USDA Zone 5a. The average last spring frost is May 7 and the first fall frost is October 14, giving you a growing season of approximately 160 days.

At an elevation of 3,428 feet, Calgary receives approximately 26.9 inches of rainfall annually with predominantly dark brown chernozem soil. Summer highs average 75ยฐF, so choose short-season varieties of Horehound to ensure they mature before fall.

Calgary, AB (Zone 5a) Moderate season
160 days
Last Spring Frost May 7
160 growing days
First Fall Frost October 14

Calgary Soil Profile

Soil Type

Dark Brown Chernozem

Soil pH

6.0-7.0

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 8 – Sep 2
Recommended (50%) ✓ Fits season (43 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 8 – Sep 2
Safe Start (90%) ✓ Fits season (43 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 8 – Sep 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.

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

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€” 1.1" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 2.1" 0" โ„๏ธ Dormant
Apr โ€” 2.5" 0" โ„๏ธ Dormant
May 2.2" 3.3" 0" โœ… Rainfall sufficient
Jun 2.2" 3.3" 0" โœ… Rainfall sufficient
Jul 2.2" 3.1" 0" โœ… Rainfall sufficient
Aug 2.2" 2.9" 0" โœ… Rainfall sufficient
Sep 2.2" 2.1" 0.1" ๐Ÿ’ง Light watering
Oct 2.2" 2" 0.2" ๐Ÿ’ง Light watering
Nov โ€” 1.9" 0" โ„๏ธ Dormant
Dec โ€” 1.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Calgary). 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 ~516 GDD — county provides 1,000 GDD Excellent fit

Horehound Planting Timeline โ€” Calgary, AB

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 โ€“ May 28
Harvest July 30 Jul 30 โ€“ Sep 24

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: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

160 days in Calgary

Growing Tips for Calgary

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 Calgary, AB?

Calgary is in Zone 5a with an average last frost of May 7. Plan your Horehound planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Calgary, AB?

Calgary, Alberta is in USDA Hardiness Zone 5a. The average last spring frost is May 7 and first fall frost is October 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Calgary gardeners in Zone 5a 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 Calgary, AB. Local conditions may vary. Last updated: April 2026.