When to Plant Shiso in Blackford County, IN
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.
Blackford County, Indiana is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 16, giving you a growing season of approximately 173 days.
At an elevation of 729 feet, Blackford County receives approximately 32.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Shiso during the growing season.
Blackford County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7
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 Blackford County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (6.0–7.0) is within Shiso's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Blackford County is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.8%) — Shiso will thrive.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Aug 07 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Jun | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Aug | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Sep | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Blackford 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 — Blackford County, IN
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 8 | Mar 8 – Mar 22 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Direct Sow | May 3 | May 3 – May 24 |
| Harvest | July 5 | Jul 5 – Aug 30 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
173 days in Blackford County
Growing Tips for Shiso in Blackford County
Direct sow Shiso outdoors after April 26 in Blackford 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 Blackford County, IN?
Blackford County is in Zone 5b with an average last frost of April 26. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Blackford County, IN?
Blackford County, Indiana is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 16.
Plan Your Garden with Confidence
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