When to Plant Shiso in Allen County, KY
May in the garden — Allen County, Kentucky
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Allen County, Kentucky.
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Start shiso indoors
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
June prep starts now
- First harvests: shiso
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.
Allen County, Kentucky is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 29, giving you a growing season of approximately 203 days.
At an elevation of 3,915 feet, Allen County receives approximately 42.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Shiso during the growing season.
Allen County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.8
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 Allen County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (5.5–6.8) is within Shiso's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Allen County is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Shiso.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Shiso.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Aug 20 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 | — | 3.7" | 0" | ❄️ Dormant |
| Feb | — | 3.1" | 0" | ❄️ Dormant |
| Mar | — | 4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jun | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jul | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Sep | 4.3" | 3" | 1.3" | 💧 Light watering |
| Oct | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 3.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Allen 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 — Allen County, KY
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 19 | Feb 19 – Mar 5 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 16 | Apr 16 – May 7 |
| Harvest | June 18 | Jun 18 – Aug 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| 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: ideal
🗺️ USDA Zone
Zone 7a
📆 Growing Season
203 days in Allen County
Growing Tips for Shiso in Allen County
Direct sow Shiso outdoors after April 09 in Allen County when soil has warmed and frost danger has passed.
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 Allen County, KY?
Allen County is in Zone 7a with an average last frost of April 9. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Allen County, KY?
Allen County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 29.
Your Allen County Garden Planner — Free
A 24-page printable planner built for Allen County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.