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When to Plant Shiso in Tehama County, CA

Shiso (perilla) is a fragrant Japanese herb with large, ruffled leaves in green or purple varieties. It has a unique flavor combining mint, basil, and anise.

Tehama County, California is in USDA Zone 8b. The average last spring frost is March 6 and the first fall frost is November 28, giving you a growing season of approximately 267 days.

At an elevation of 78 feet, Tehama County receives approximately 44 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Shiso to ensure they mature before fall.

Tehama County, CA (Zone 8b) Long season
267 days
Last Spring Frost March 6
267 growing days
First Fall Frost November 28

Tehama County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (144 days to spare)
Start indoors: Jan 5 Transplant: Mar 9 🍅 Harvest: May 4 – Jun 29
Recommended (50%) ✓ Fits season (141 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 15 – Jul 10
Safe Start (90%) ✓ Fits season (119 days to spare)
Start indoors: Feb 28 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 22

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 878 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Shiso needs ~690 GDD — county provides 3,070 GDD Excellent fit

Shiso Planting Timeline โ€” Tehama County, CA

Shiso Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 โ€“ Jan 30
Transplant Outdoors March 20 Mar 20 โ€“ Apr 3
Direct Sow March 13 Mar 13 โ€“ Apr 3
Harvest May 15 May 15 โ€“ Jul 10

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“70 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 8b

Growing Season

267 days

Growing Tips for Tehama County

Direct sow after last frost or start indoors. Both green and red varieties are available. Pinch tips to encourage bushiness. Self-sows prolifically; deadhead to control.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Shiso in Tehama County, CA?

Tehama County is in Zone 8b with an average last frost of March 6. Plan your Shiso planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Tehama County, CA?

Tehama County, California is in USDA Hardiness Zone 8b. The average last spring frost is March 6 and first fall frost is November 28.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Tehama County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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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 Tehama County, CA. Local conditions may vary. Last updated: April 2026.