When to Plant Shiso in Jefferson County, NY
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.
Jefferson County, New York is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 6, giving you a growing season of approximately 149 days.
At an elevation of 468 feet, Jefferson County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Shiso during the growing season.
Jefferson County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.2
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 Jefferson County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (4.9–6.2) overlaps with Shiso's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Jefferson County is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Shiso.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Jul 28 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 | — | 2.6" | 0" | ❄️ Dormant |
| Feb | — | 3" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | — | 3.3" | 0" | ❄️ Dormant |
| May | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Jun | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Jul | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Oct | 4.3" | 3.3" | 1" | 💧 Light watering |
| Nov | — | 3.3" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Jefferson 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 — Jefferson County, NY
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 15 | Mar 15 – Mar 29 |
| Transplant Outdoors | May 31 | May 31 – Jun 14 |
| Direct Sow | May 17 | May 17 – Jun 7 |
| Harvest | July 26 | Jul 26 – Sep 20 |
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 | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| 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 4b
📆 Growing Season
149 days in Jefferson County
Growing Tips for Shiso in Jefferson County
Direct sow Shiso outdoors after May 10 in Jefferson 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 Jefferson County, NY?
Jefferson County is in Zone 4b with an average last frost of May 10. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, NY?
Jefferson County, New York is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 6.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Jefferson County gardeners in Zone 4b 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.