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When to Plant Shiso in Bibb County, GA

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.

Bibb County, Georgia is in USDA Zone 8a. The average last spring frost is March 22 and the first fall frost is November 6, giving you a growing season of approximately 229 days.

At an elevation of 218 feet, Bibb County receives approximately 60.7 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94ยฐF, providing good warmth for Shiso during the growing season. Clay soil retains moisture well for Shiso, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Shiso root diseases.

Bibb County, GA (Zone 8a) Long season
229 days
Last Spring Frost March 22
229 growing days
First Fall Frost November 6

Bibb County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Start indoors: Jan 21 Transplant: Mar 25 🍅 Harvest: May 20 – Jul 15
Recommended (50%) ✓ Fits season (103 days to spare)
Start indoors: Feb 1 Transplant: Apr 5 🍅 Harvest: May 31 – Jul 26
Safe Start (90%) ✓ Fits season (101 days to spare)
Start indoors: Feb 20 Transplant: Apr 24 🍅 Harvest: Jun 19 – Aug 14

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 Bibb County

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

Soil pH

Your soil pH (5.5โ€“6.6) is within Shiso's preferred range (5.5โ€“7.0).

Soil Texture

The clay loam soil in Bibb County is excellent for Shiso โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Shiso.

Organic Matter

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

How to Plant Shiso

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Shiso

5
successive plantings in your 229-day season

Sow every 5.7 weeks. Last sowing by Aug 28 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Shiso

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

Month Shiso Needs Rainfall You Supplement Action
Jan โ€” 4.9" 0" โ„๏ธ Dormant
Feb โ€” 5.3" 0" โ„๏ธ Dormant
Mar 4.3" 6" 0" โœ… Rainfall sufficient
Apr 4.3" 5.1" 0" โœ… Rainfall sufficient
May 4.3" 5.1" 0" โœ… Rainfall sufficient
Jun 4.3" 5.4" 0" โœ… Rainfall sufficient
Jul 4.3" 5.5" 0" โœ… Rainfall sufficient
Aug 4.3" 6.3" 0" โœ… Rainfall sufficient
Sep 4.3" 4.7" 0" โœ… Rainfall sufficient
Oct 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Nov 4.3" 4.4" 0" โœ… Rainfall sufficient
Dec โ€” 4.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Bibb County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Shiso 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" โ€” every day above 50ยฐF 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.

Shiso needs ~1,230 GDD — county provides 4,694 GDD Excellent fit

Shiso Planting Timeline โ€” Bibb County, GA

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 1 Feb 1 โ€“ Feb 15
Transplant Outdoors April 5 Apr 5 โ€“ Apr 19
Direct Sow March 29 Mar 29 โ€“ Apr 19
Harvest May 31 May 31 โ€“ Jul 26

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March 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

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

229 days in Bibb County

Growing Tips for Shiso in Bibb County

Direct sow Shiso outdoors after March 22 in Bibb County when soil has warmed and frost danger has passed.

With Bibb County's clay soil (33% clay), work in 3-4 inches of compost before planting Shiso. Avoid tilling when soil is wet to prevent compaction.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Shiso in Bibb County, GA?

Bibb County is in Zone 8a with an average last frost of March 22. Plan your Shiso planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Bibb County, GA?

Bibb County, Georgia is in USDA Hardiness Zone 8a. The average last spring frost is March 22 and first fall frost is November 6.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Bibb County, GA. Local conditions may vary. Last updated: April 2026.