When to Plant Shiso in Grande Prairie, AB
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.
Grande Prairie, Alberta is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is October 9, giving you a growing season of approximately 140 days.
At an elevation of 2,194 feet, Grande Prairie receives approximately 19 inches of rainfall annually with predominantly dark brown chernozem soil. Summer highs average 75°F, so choose short-season varieties of Shiso to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Shiso successfully. Mulch heavily to conserve soil moisture.
Grande Prairie Soil Profile
Soil Type
Dark Brown Chernozem
Soil pH
6.0-7.0
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.
How to Plant Shiso
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 | — | 0.7" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.1" | 0" | ❄️ Dormant |
| Apr | — | 1.9" | 0" | ❄️ Dormant |
| May | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Jun | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Jul | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Aug | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Grande Prairie). 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 — Grande Prairie, AB
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 27 | Mar 27 – Apr 10 |
| Transplant Outdoors | June 12 | Jun 12 – Jun 26 |
| Direct Sow | May 29 | May 29 – Jun 19 |
| Harvest | August 7 | Aug 7 – Oct 2 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.5–7 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
140 days in Grande Prairie
Growing Tips for Shiso in Grande Prairie
Grande Prairie receives only 19" of rain annually. Shiso needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Grande Prairie, AB?
Grande Prairie is in Zone 4a with an average last frost of May 22. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grande Prairie, AB?
Grande Prairie, Alberta is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is October 9.
Your Grande Prairie Garden Planner — Free
A 24-page printable planner built for Grande Prairie (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.