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When to Plant Corn in Trinity County, CA

Trinity County, California Zone 8b May

Top priorities for Trinity County, California gardeners in May

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

Avg. last frost April 19
Avg. first frost October 25
Soil temp (4") 69°F
Watering Critical
Pest pressure Moderate
Daylight 14.3 hrs
Before June arrives, get these ready
  • First harvests: corn

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Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

Trinity County, California is in USDA Zone 8b. The average last spring frost is April 19 and the first fall frost is October 25, giving you a growing season of approximately 189 days.

At an elevation of 61 feet, Trinity County receives approximately 30.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 79°F, so choose short-season varieties of Corn to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Corn will need more frequent watering and organic matter to retain nutrients.

Trinity County, CA (Zone 8b) Moderate season
189 days
Last Spring Frost April 19
189 growing days
First Fall Frost October 25
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Trinity County Soil Profile

Soil Type

Sandy Loam

Soil pH

6-7.1

Drainage

Well Drained

How Much Corn to Grow

1-2 ears
Average yield per plant
15
Plants per person
30 sq ft
Space per person

For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In Trinity County's 189-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Corn

Corn needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Corn Needs Rainfall You Supplement Action
Jan 6.2" 0" ❄️ Dormant
Feb 6.6" 0" ❄️ Dormant
Mar 5" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 0.9" 3.4" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.3" 4" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 2.9" 0" ❄️ Dormant
Dec 4.9" 0" ❄️ Dormant

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

Corn Planting Timeline — Trinity County, CA

Corn Planting Calendar

Activity When Date Range
Direct Sow April 26 Apr 26 – May 17
Harvest June 28 Jun 28 – Aug 23

Plant 1" deep · 12" apart · Rows 36" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 8b

📆 Growing Season

189 days in Trinity County

Growing Tips for Trinity County

Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Trinity County, CA?

Trinity County is in Zone 8b with an average last frost of April 19. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Trinity County, CA?

Trinity County, California is in USDA Hardiness Zone 8b. The average last spring frost is April 19 and first fall frost is October 25.

🌱

Your Trinity County Garden Planner — Free

A 24-page printable planner built for Trinity County (Zone 8b). 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 Trinity 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.