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When to Plant Rosemary in Kings County, CA

Kings County, California Zone 9a May

Your May planting checklist for Kings County, California

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

Avg. last frost February 14
Avg. first frost December 2
Soil temp (4") 72°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. It's harvest week for rosemary

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

To set up a strong June, finish these tasks
  • First harvests: rosemary

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Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.

Kings County, California is in USDA Zone 9a. The average last spring frost is February 14 and the first fall frost is December 2, giving you a growing season of approximately 291 days.

At an elevation of 2,065 feet, Kings County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Rosemary may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Rosemary successfully. Mulch heavily to conserve soil moisture.

Kings County, CA (Zone 9a) Year-round
291 days
Last Spring Frost February 14
291 growing days
First Fall Frost December 2
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Kings County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Transplant: Feb 7 🍅 Harvest: May 2 – Sep 19
Recommended (50%) ✓ Fits season (60 days to spare)
Transplant: Feb 21 🍅 Harvest: May 16 – Oct 3
Safe Start (90%) ✓ Fits season (58 days to spare)
Transplant: Mar 15 🍅 Harvest: Jun 7 – Oct 25

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 Kings County

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

Soil pH

Your soil pH (6.5–7.4) is within Rosemary's preferred range (6.0–7.5).

Soil Texture

The loam soil in Kings County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Rosemary.

How to Plant Rosemary

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

Succession Planting Rosemary

4
successive plantings in your 291-day season

Sow every 9.1 weeks. Last sowing by Jun 05 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.3″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 92 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Rosemary

Rosemary needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Rosemary Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 1.3" 4" 0" ✅ Rainfall sufficient
Mar 1.3" 3.2" 0" ✅ Rainfall sufficient
Apr 1.3" 1.4" 0" ✅ Rainfall sufficient
May 1.3" 0.5" 0.8" 🚿 Regular watering
Jun 1.3" 0.1" 1.2" 🚿 Regular watering
Jul 1.3" 0" 1.3" 🚿 Regular watering
Aug 1.3" 0" 1.3" 🚿 Regular watering
Sep 1.3" 0.2" 1.1" 🚿 Regular watering
Oct 1.3" 0.7" 0.6" 💧 Light watering
Nov 1.3" 1.9" 0" ✅ Rainfall sufficient
Dec 1.3" 3.2" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Kings County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Rosemary 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.

Rosemary needs ~3,445 GDD — county provides 7,738 GDD Excellent fit

Rosemary Planting Timeline — Kings County, CA

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors February 21 Feb 21 – Mar 7
Harvest May 16 May 16 – Oct 3

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Only during dry spells

📅 Days to Maturity

80–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9a

📆 Growing Season

291 days in Kings County

Growing Tips for Rosemary in Kings County

Direct sow Rosemary outdoors after February 14 in Kings County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Kings County, provide afternoon shade for Rosemary and water deeply in the morning.

General growing tips

Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rosemary in Kings County, CA?

Kings County is in Zone 9a with an average last frost of February 14. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kings County, CA?

Kings County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 14 and first fall frost is December 2.

🌱

Your Kings County Garden Planner — Free

A 24-page printable planner built for Kings County (Zone 9a). 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 Kings 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.