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When to Plant Rue in San Joaquin County, CA

San Joaquin County, California Zone 9b May

This month in San Joaquin County, California

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

Avg. last frost February 4
Avg. first frost December 6
Soil temp (4") 77°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Harvest rue as they ripen

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Looking ahead to June
  • First harvests: rue

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Rue is a bitter, aromatic perennial herb with bluish-green foliage used historically in medicine and as a pest deterrent. Handle with care as its sap can cause skin irritation.

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 Rue during the growing season. With low rainfall, drip irrigation is essential for growing Rue 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
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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 5 – Jun 7
Recommended (50%) ✓ Fits season (165 days to spare)
Transplant: Feb 11 🍅 Harvest: Apr 22 – Jun 24
Safe Start (90%) ✓ Fits season (149 days to spare)
Transplant: Mar 12 🍅 Harvest: May 21 – 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 Rue's growing requirements.

Soil pH

Your soil pH (6.4–7.8) overlaps with Rue's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Rue

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

Succession Planting Rue

5
successive plantings in your 305-day season

Sow every 8 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 Rue

Rue 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 Rue 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.

Rue 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.

Rue needs ~1,580 GDD — county provides 6,043 GDD Excellent fit

Rue Planting Timeline — San Joaquin County, CA

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors February 11 Feb 11 – Feb 25
Harvest April 22 Apr 22 – 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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

305 days in San Joaquin County

Growing Tips for Rue in San Joaquin County

Direct sow Rue 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. Rue needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors or direct sow. Plant in well-drained soil. Wear gloves when handling as sap can cause phytophotodermatitis. Prune in early spring.

Companion Planting

Good Companions

Avoid Planting Near

  • Basil
  • Sage

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rue in San Joaquin County, CA?

San Joaquin County is in Zone 9b with an average last frost of February 4. Plan your Rue 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.

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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 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.