When to Plant Shiso in Juneau City and Borough, AK
Your May game plan for Juneau City and Borough, Alaska
Your garden in Juneau City and Borough, Alaska is working on a schedule, even when you're not. Here's where you should be this May.
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Move shiso into the garden
Your last frost (May 3) has passed. These warm-season crops can handle outdoor soil now.
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Plant shiso from seed, right in the garden
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
June prep starts now
- Starting indoors: 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.
Juneau City and Borough, Alaska is in USDA Zone 7a. The average last spring frost is May 3 and the first fall frost is October 2, giving you a growing season of approximately 152 days.
At an elevation of 930 feet, Juneau City and Borough receives approximately 35.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 57°F, so choose short-season varieties of Shiso to ensure they mature before fall.
Juneau City and Borough Soil Profile
Soil Type
Silt Loam
Soil pH
5.1-6.5
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 Juneau City and Borough
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (5.1–6.5) overlaps with Shiso's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Juneau City and Borough is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (6.7%) — Shiso will thrive.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Jul 24 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" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | — | 1" | 0" | ❄️ Dormant |
| May | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jun | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Jul | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 5.3" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.5" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Juneau City and Borough). 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 — Juneau City and Borough, AK
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 15 | Mar 15 – Mar 29 |
| Transplant Outdoors | May 17 | May 17 – May 31 |
| Direct Sow | May 10 | May 10 – May 31 |
| Harvest | July 12 | Jul 12 – Sep 6 |
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 | Harvest |
| 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: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
152 days in Juneau City and Borough
Growing Tips for Shiso in Juneau City and Borough
Direct sow Shiso outdoors after May 03 in Juneau City and Borough 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 Juneau City and Borough, AK?
Juneau City and Borough is in Zone 7a with an average last frost of May 3. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Juneau City and Borough, AK?
Juneau City and Borough, Alaska is in USDA Hardiness Zone 7a. The average last spring frost is May 3 and first fall frost is October 2.
Your Juneau City and Borough Garden Planner — Free
A 24-page printable planner built for Juneau City and Borough (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.