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When to Plant Collard Greens in Tuolumne County, CA

Tuolumne County, California Zone 9b May

Your May game plan for Tuolumne County, California

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

Avg. last frost April 25
Avg. first frost October 27
Soil temp (4") 62°F
Watering Critical
Pest pressure Moderate
Daylight 14.1 hrs
  1. Get collard greens seeds going inside

    Label every cell. You will absolutely forget which is which otherwise.

To set up a strong June, finish these tasks
  • 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.

Tuolumne County, California is in USDA Zone 9b. The average last spring frost is April 25 and the first fall frost is October 27, giving you a growing season of approximately 185 days.

At an elevation of 2,990 feet, Tuolumne County receives approximately 37.7 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Collard Greens during the growing season.

Tuolumne County, CA (Zone 9b) Moderate season
185 days
Last Spring Frost April 25
185 growing days
First Fall Frost October 27
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Tuolumne County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🍅 Harvest: Jun 9 – Aug 11
Recommended (50%) ✓ Fits season (66 days to spare)
Start indoors: Mar 28 Transplant: Apr 25 🍅 Harvest: Jun 20 – Aug 22
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: May 23 Transplant: Jun 20 🍅 Harvest: Aug 15 – Oct 17

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 Tuolumne County

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

Soil pH

Your soil pH (6.6–7.5) is more alkaline than Collard Greens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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

3
successive plantings in your 185-day season

Sow every 6.3 weeks. Last sowing by Aug 13 to harvest before frost.

For a dedicated fall crop, sow by Sep 01.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 7.8" 0" ❄️ Dormant
Feb 8.2" 0" ❄️ Dormant
Mar 6.7" 0" ❄️ Dormant
Apr 3.5" 2.8" 0.7" 💧 Light watering
May 3.5" 1.1" 2.4" 🚿 Regular watering
Jun 3.5" 0.2" 3.3" 🚿 Regular watering
Jul 3.5" 0" 3.5" 🚿 Regular watering
Aug 3.5" 0" 3.5" 🚿 Regular watering
Sep 3.5" 0.4" 3.1" 🚿 Regular watering
Oct 3.5" 1.5" 2" 🚿 Regular watering
Nov 3" 0" ❄️ Dormant
Dec 6.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Tuolumne 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 ~1,040 GDD — county provides 2,960 GDD Excellent fit

Collard Greens Planting Timeline — Tuolumne County, CA

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 4 Apr 4 – Apr 25
Harvest June 20 Jun 20 – Aug 22
Fall Sowing September 1 Sep 1 – Sep 15

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

185 days in Tuolumne County

Growing Tips for Collard Greens in Tuolumne County

Direct sow Collard Greens outdoors after April 25 in Tuolumne County when soil has warmed and frost danger has passed.

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 Tuolumne County, CA?

Tuolumne County is in Zone 9b with an average last frost of April 25. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tuolumne County, CA?

Tuolumne County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 25 and first fall frost is October 27.

🌱

Your Tuolumne County Garden Planner — Free

A 24-page printable planner built for Tuolumne 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 Tuolumne 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.