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When to Plant Collard Greens in Kern County, CA

Kern County, California Zone 9b May

Kern County, California gardeners: here's your May plan

Your garden in Kern County, California is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost February 28
Avg. first frost November 29
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. Pick collard greens

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Looking ahead to June
  • First harvests: collard greens

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Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.

Kern County, California is in USDA Zone 9b. The average last spring frost is February 28 and the first fall frost is November 29, giving you a growing season of approximately 274 days.

At an elevation of 389 feet, Kern County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Collard Greens may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Collard Greens successfully. Mulch heavily to conserve soil moisture.

Kern County, CA (Zone 9b) Year-round
274 days
Last Spring Frost February 28
274 growing days
First Fall Frost November 29
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Kern County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (155 days to spare)
Start indoors: Jan 23 Transplant: Feb 20 🍅 Harvest: Apr 17 – Jun 19
Recommended (50%) ✓ Fits season (155 days to spare)
Start indoors: Jan 31 Transplant: Feb 28 🍅 Harvest: Apr 25 – Jun 27
Safe Start (90%) ✓ Fits season (137 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🍅 Harvest: Jun 2 – Aug 4

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 Kern County

How your county's soil matches Collard Greens's growing requirements.

Soil pH

Your soil pH (6.2–7.7) overlaps with Collard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Kern County is excellent for Collard Greens — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Collard Greens.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Collard Greens.

How to Plant Collard Greens

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Collard Greens

5
successive plantings in your 274-day season

Sow every 6.3 weeks. Last sowing by Sep 15 to harvest before frost.

For a dedicated fall crop, sow by Oct 04.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.3″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,296 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Collard Greens

Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Collard Greens Needs Rainfall You Supplement Action
Jan 3.9" 0" ❄️ Dormant
Feb 3.5" 3.4" 0.1" 💧 Light watering
Mar 3.5" 2.4" 1.1" 💧 Light watering
Apr 3.5" 1.2" 2.3" 🚿 Regular watering
May 3.5" 0.5" 3" 🚿 Regular watering
Jun 3.5" 0.1" 3.4" 🚿 Regular watering
Jul 3.5" 0" 3.5" 🚿 Regular watering
Aug 3.5" 0" 3.5" 🚿 Regular watering
Sep 3.5" 0.2" 3.3" 🚿 Regular watering
Oct 3.5" 0.7" 2.8" 🚿 Regular watering
Nov 3.5" 1.7" 1.8" 🚿 Regular watering
Dec 2.8" 0" ❄️ Dormant

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

Collard Greens 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.

Collard Greens needs ~1,722 GDD — county provides 7,287 GDD Excellent fit

Collard Greens Planting Timeline — Kern County, CA

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors February 28 Feb 28 – Mar 14
Direct Sow February 7 Feb 7 – Feb 28
Harvest April 25 Apr 25 – Jun 27
Fall Sowing October 4 Oct 4 – Oct 18

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Transplant Outdoors Direct Sow
March Transplant Outdoors
April Harvest
May Harvest
June Harvest
July
August
September
October Fall Sowing
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 2-3 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

274 days in Kern County

Growing Tips for Collard Greens in Kern County

Direct sow Collard Greens outdoors after February 28 in Kern County when soil has warmed and frost danger has passed.

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

Common pests for Collard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Collard Greens in Kern County, CA?

Kern County is in Zone 9b with an average last frost of February 28. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kern County, CA?

Kern County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 28 and first fall frost is November 29.

🌱

Your Kern County Garden Planner — Free

A 24-page printable planner built for Kern 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 Kern 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.