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When to plant Cabbage in Harmony, CA

Aim to plant Cabbage in Harmony on or after March 2; the window stays open through March 23. Harmony's 231-day frost-free season gives you enough for a full main crop and a short fall succession. A second sowing from September 14 to September 28 extends the harvest into fall.

When to Plant Cabbage in Harmony, CA

Cabbage
San Luis Obispo County, California Zone 10a July

What to do in July

July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in San Luis Obispo County, California.

Avg. last frost March 23
Avg. first frost November 9
Soil temp (4") 90°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Basket week: cabbage

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Cabbage is a versatile cool-season crop that forms dense, leafy heads in green, red, or savoy varieties. It is a staple for coleslaw, sauerkraut, and many global cuisines.

Harmony, California is in USDA Zone 10a. The average last spring frost is March 23 and the first fall frost is November 9, giving you a growing season of approximately 231 days.

At an elevation of 2,412 feet, San Luis Obispo County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, so Cabbage may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Cabbage successfully. Mulch heavily to conserve soil moisture.

Harmony, CA (Zone 10a) Long season
231 days
Last Spring Frost March 23
231 growing days
First Fall Frost November 9

Harmony Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Cabbage Planting Risk Windows

Early Start (70% safe) ✓ Fits season (122 days to spare)
Start indoors: Feb 5 Transplant: Mar 5 🍅 Harvest: May 7 – Jul 2
Recommended (50%) ✓ Fits season (112 days to spare)
Start indoors: Feb 23 Transplant: Mar 23 🍅 Harvest: May 25 – Jul 20
Safe Start (90%) ✓ Fits season (110 days to spare)
Start indoors: Mar 19 Transplant: Apr 16 🍅 Harvest: Jun 18 – Aug 13

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 Harmony

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

Soil pH

Your soil pH (6.6–7.8) overlaps with Cabbage's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Cabbage.

How to Plant Cabbage

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 Cabbage

4
successive plantings in your 231-day season

Sow every 6.9 weeks. Last sowing by Aug 01 to harvest before frost.

For a dedicated fall crop, sow by Sep 14.

Cabbage Water Budget

Plant needs
0.9″/week
Rainfall provides
0.3″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,395 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Cabbage

Cabbage needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Cabbage Needs Rainfall You Supplement Action
Jan 4" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 3.9" 2.8" 1.1" 💧 Light watering
Apr 3.9" 1.6" 2.3" 🚿 Regular watering
May 3.9" 0.5" 3.4" 🚿 Regular watering
Jun 3.9" 0.1" 3.8" 🚿 Regular watering
Jul 3.9" 0" 3.9" 🚿 Regular watering
Aug 3.9" 0" 3.9" 🚿 Regular watering
Sep 3.9" 0.2" 3.7" 🚿 Regular watering
Oct 3.9" 0.8" 3.1" 🚿 Regular watering
Nov 3.9" 1.8" 2.1" 🚿 Regular watering
Dec 2.8" 0" ❄️ Dormant

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

Cabbage 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.

Cabbage needs ~1,880 GDD — county provides 5,428 GDD Excellent fit

Cabbage Planting Timeline — Harmony, CA

Cabbage Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 – Mar 9
Transplant Outdoors March 23 Mar 23 – Apr 6
Direct Sow March 2 Mar 2 – Mar 23
Harvest May 25 May 25 – Jul 20
Fall Sowing September 14 Sep 14 – Sep 28

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 1-2 times/week

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

231 days in San Luis Obispo County

Growing Tips for Cabbage in Harmony

Direct sow Cabbage outdoors after March 23 in San Luis Obispo County when soil has warmed and frost danger has passed.

Summer highs in San Luis Obispo County reach 98°F — grow Cabbage as a spring or fall crop. Use shade cloth if planting in summer.

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

San Luis Obispo County receives only 18" of rain annually. Cabbage needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 4-6 weeks before last frost. Space plants 18-24 inches apart. Keep soil evenly moist to prevent heads from splitting.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

When should I plant Cabbage in Harmony, CA?

In Harmony, CA, plant Cabbage after the last frost (around March 23) and before the first frost (around November 9). Best results when soil holds above 50°F.

What growing zone is Harmony, CA for Cabbage?

Harmony sits in USDA Zone 10a. Cabbage grows reliably in zones 1a through 10b, so it's a good fit here.

Can Cabbage grow in Harmony's climate?

Yes — Cabbage grows well in Harmony's temperate climate. Harmony averages a 231-day frost-free season, with last frost around March 23 and first frost around November 9.

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A 22-page printable planner built for San Luis Obispo County (Zone 10a). 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 Luis Obispo County, CA. Local conditions may vary. Last updated: July 2026.