Blog

When to Plant Horehound in San Joaquin County, CA

San Joaquin County, California Zone 9b May

Your May planting checklist for San Joaquin County, California

Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 4
Avg. first frost December 6
Soil temp (4") 77°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Basket week: horehound

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Before June arrives, get these ready
  • First harvests: horehound

Instant PDF download. No spam, unsubscribe any time.

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

San Joaquin County, California is in USDA Zone 9b. The average last spring frost is February 4 and the first fall frost is December 6, giving you a growing season of approximately 305 days.

At an elevation of 220 feet, San Joaquin County receives approximately 15 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Horehound during the growing season. With low rainfall, drip irrigation is essential for growing Horehound successfully. Mulch heavily to conserve soil moisture.

San Joaquin County, CA (Zone 9b) Year-round
305 days
Last Spring Frost February 4
305 growing days
First Fall Frost December 6

San Joaquin County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (175 days to spare)
Transplant: Jan 25 🍅 Harvest: Apr 12 – Jun 7
Recommended (50%) ✓ Fits season (165 days to spare)
Transplant: Feb 11 🍅 Harvest: Apr 29 – Jun 24
Safe Start (90%) ✓ Fits season (149 days to spare)
Transplant: Mar 12 🍅 Harvest: May 28 – Jul 23

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 San Joaquin County

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

Soil pH

Your soil pH (6.4–7.8) is within Horehound's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Horehound.

How to Plant Horehound

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

Succession Planting Horehound

4
successive plantings in your 305-day season

Sow every 8.6 weeks. Last sowing by Sep 07 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 961 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 2.9" 0" ❄️ Dormant
Feb 2.2" 3.1" 0" ✅ Rainfall sufficient
Mar 2.2" 2.6" 0" ✅ Rainfall sufficient
Apr 2.2" 1.2" 1" 💧 Light watering
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.2" 2" 🚿 Regular watering
Oct 2.2" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.3" 0.9" 💧 Light watering
Dec 2.2" 2.6" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in San Joaquin 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 ~1,629 GDD — county provides 6,043 GDD Excellent fit

Horehound Planting Timeline — San Joaquin County, CA

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors February 11 Feb 11 – Feb 25
Harvest April 29 Apr 29 – Jun 24

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

75–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

305 days in San Joaquin County

Growing Tips for Horehound in San Joaquin County

Direct sow Horehound outdoors after February 04 in San Joaquin County when soil has warmed and frost danger has passed.

San Joaquin County receives only 15" 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 San Joaquin County, CA?

San Joaquin County is in Zone 9b with an average last frost of February 4. Plan your Horehound planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Joaquin County, CA?

San Joaquin County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 4 and first fall frost is December 6.

🌱

Your San Joaquin County Garden Planner — Free

A 24-page printable planner built for San Joaquin County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for San Joaquin County, CA. 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.