When to Plant Shiso in Chatham 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.
Chatham County, Georgia is in USDA Zone 8b. The average last spring frost is March 5 and the first fall frost is November 23, giving you a growing season of approximately 263 days.
At an elevation of 398 feet, Chatham County receives approximately 51.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 91°F, providing good warmth for Shiso during the growing season. Sandy soil warms quickly in spring — great for early planting — but Shiso will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Shiso root diseases.
Chatham County Soil Profile
Soil Type
Sandy Loam
Soil pH
5-6.1
Drainage
Well Drained
Plant Planting Risk Windows
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 Chatham County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (5.0–6.1) overlaps with Shiso's range (5.5–7.0), though not a perfect match.
Soil Texture
Sandy soil in Chatham County warms quickly in spring but drains fast. Shiso will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Shiso.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Shiso.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Sep 14 to harvest before frost.
Plant Water Budget
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 | — | 4.3" | 0" | ❄️ Dormant |
| Feb | — | 4.4" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| May | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jun | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 6" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | 4.3" | 4" | 0.3" | 💧 Light watering |
| Dec | — | 4.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Chatham County). Supplement amounts are based on average rainfall — 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" — 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.
Shiso Planting Timeline — Chatham County, GA
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 15 | Jan 15 – Jan 29 |
| Transplant Outdoors | March 19 | Mar 19 – Apr 2 |
| Direct Sow | March 12 | Mar 12 – Apr 2 |
| Harvest | May 14 | May 14 – Jul 9 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 8b
📆 Growing Season
263 days in Chatham County
Growing Tips for Shiso in Chatham County
Direct sow Shiso outdoors after March 05 in Chatham County when soil has warmed and frost danger has passed.
Sandy soil in Chatham County dries quickly — mulch Shiso with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
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 →
Shiso in Other Locations
Frequently Asked Questions
When should I plant Shiso in Chatham County, GA?
Chatham County is in Zone 8b with an average last frost of March 5. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Chatham County, GA?
Chatham County, Georgia is in USDA Hardiness Zone 8b. The average last spring frost is March 5 and first fall frost is November 23.
Plan Your Garden with Confidence
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