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When to Plant Horehound in USDA Zone 4a

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

In Zone 4a, the average last spring frost is around May 6 and the first fall frost is around September 28, giving you a growing season of approximately 145 days.

Zone 4a Short season
145 days
Last Spring Frost May 6
145 growing days
First Fall Frost September 28

Horehound Planting Timeline — Zone 4a

Where Is USDA Zone 4a?

The map below highlights the states that contain Zone 4a. Click any state to see the Horehound planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Horehound Planting Calendar — Zone 4a

Activity When Date Range
Transplant Outdoors May 13 May 13 – May 27
Harvest July 29 Jul 29 – Sep 23

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

Month-by-Month Timeline

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

Free Zone 4a Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4a with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

Days to Maturity

75–90 days

Soil pH

6 – 8

Zone Temperature Range

-30°F to -25°F average annual minimum

Growing Season

145 days (Zone 4a average)

Planting Specifications

Planting Depth0.5 inches
Plant Spacing8 inches apart
Row Spacing12 inches between rows

Succession Planting Horehound in Zone 4a

2
successive plantings in Zone 4a's ~145-day season

Sow every 8.6 weeks for continuous harvest throughout the season.

Growing Tips for Horehound in Zone 4a

Zone 4a has a short growing season (~145 days). Start Horehound indoors early and use season-extension techniques like row covers and cold frames.

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

Level Up Your Garden

Saving Horehound Seeds

Recommended for Your Garden

💡
LED Grow Lights $25-60

Full-spectrum LED lights for starting seeds indoors when daylight is limited.

🔥
Seedling Heat Mat $15-35

Warm soil for faster germination of heat-loving crops like tomatoes and peppers.

🪡
Floating Row Covers $12-30

Protect plants from frost, wind, and pests while letting light and water through.

Related Plants

Frequently Asked Questions

When should I plant Horehound in Zone 4a?

In Zone 4a, plan your Horehound planting around the average last frost date of May 6. Transplant seedlings around May 13.

Can Horehound grow in Zone 4a?

Yes, Horehound can grow well in Zone 4a, hardy in USDA zones 3a through 10b. Zone 4a has a growing season of approximately 145 days, which is sufficient for Horehound (75-90 days to maturity).

When can I harvest Horehound in Zone 4a?

In Zone 4a, expect to harvest Horehound from July 29 – September 23. Horehound takes 75-90 days from planting to harvest.

What is the last frost date for Zone 4a?

The average last spring frost in Zone 4a is around May 6, and the first fall frost is around September 28. This gives a growing season of approximately 145 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Horehound?

Good companion plants for Horehound include Tomatoes, Peppers. These companions can help with pest control, pollination, and nutrient sharing.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — organize your planting dates for Zone 4a, track your crops, and plan your garden season from seed to harvest.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: April 2026.