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When to Plant Horehound in Polk County, OR

Polk County, Oregon Zone 8b May

May in Polk County, Oregon — your action list

Your Polk County, Oregon garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 10
Avg. first frost October 31
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs

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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.

Polk County, Oregon is in USDA Zone 8b. The average last spring frost is April 10 and the first fall frost is October 31, giving you a growing season of approximately 204 days.

At an elevation of 331 feet, Polk County receives approximately 54.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Horehound to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Horehound root diseases.

Polk County, OR (Zone 8b) Long season
204 days
Last Spring Frost April 10
204 growing days
First Fall Frost October 31
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Polk County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (75 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 16 – Aug 11
Recommended (50%) ✓ Fits season (64 days to spare)
Transplant: Apr 17 🍅 Harvest: Jul 3 – Aug 28
Safe Start (90%) ✓ Fits season (70 days to spare)
Transplant: May 9 🍅 Harvest: Jul 25 – Sep 19

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 Polk County

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

Soil pH

Your soil pH (5.7–6.5) overlaps with Horehound's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Horehound will thrive.

How to Plant Horehound

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

Succession Planting Horehound

3
successive plantings in your 204-day season

Sow every 8.6 weeks. Last sowing by Aug 02 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/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 8.7" 0" ❄️ Dormant
Feb 5.6" 0" ❄️ Dormant
Mar 5" 0" ❄️ Dormant
Apr 2.2" 4.2" 0" ✅ Rainfall sufficient
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 2.4" 0" ✅ Rainfall sufficient
Jul 2.2" 0.9" 1.3" 🚿 Regular watering
Aug 2.2" 1.1" 1.1" 🚿 Regular watering
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 2.2" 4.5" 0" ✅ Rainfall sufficient
Nov 8.1" 0" ❄️ Dormant
Dec 8.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Polk 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 2,193 GDD Excellent fit

Horehound Planting Timeline — Polk County, OR

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors April 17 Apr 17 – May 1
Harvest July 3 Jul 3 – Aug 28

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 8b

📆 Growing Season

204 days in Polk County

Growing Tips for Horehound in Polk County

Direct sow Horehound outdoors after April 10 in Polk 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 →

Frequently Asked Questions

When should I plant Horehound in Polk County, OR?

Polk County is in Zone 8b with an average last frost of April 10. Plan your Horehound planting based on this frost date — see the calendar above for exact timing.

What planting zone is Polk County, OR?

Polk County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 10 and first fall frost is October 31.

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Your Polk County Garden Planner — Free

A 24-page printable planner built for Polk County (Zone 8b). 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 Polk County, OR. 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.