When to Plant Shiso in Sierra County, CA
Your May gardening checklist
May is a pivotal month for Sierra County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Transplant shiso outside
Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.
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Plant shiso from seed, right in the garden
Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.
Before June arrives, get these ready
- 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.
Sierra County, California is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is October 22, giving you a growing season of approximately 165 days.
At an elevation of 1,560 feet, Sierra County receives approximately 40.5 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Shiso to ensure they mature before fall.
Sierra County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.3
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 Sierra County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (6.7–7.3) overlaps with Shiso's range (5.5–7.0), though not a perfect match.
Soil Texture
The loam soil in Sierra County is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Shiso.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Aug 13 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
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 | — | 8.8" | 0" | ❄️ Dormant |
| Feb | — | 8.2" | 0" | ❄️ Dormant |
| Mar | — | 5.6" | 0" | ❄️ Dormant |
| Apr | — | 3.2" | 0" | ❄️ Dormant |
| May | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Jun | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Oct | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Nov | — | 3.7" | 0" | ❄️ Dormant |
| Dec | — | 7.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Sierra 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 — Sierra County, CA
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 22 | Mar 22 – Apr 5 |
| Transplant Outdoors | May 24 | May 24 – Jun 7 |
| Direct Sow | May 17 | May 17 – Jun 7 |
| Harvest | July 19 | Jul 19 – Sep 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| 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 6b
📆 Growing Season
165 days in Sierra County
Growing Tips for Shiso in Sierra County
Direct sow Shiso outdoors after May 10 in Sierra 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 Sierra County, CA?
Sierra County is in Zone 6b 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 Sierra County, CA?
Sierra County, California is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is October 22.
Your Sierra County Garden Planner — Free
A 24-page printable planner built for Sierra County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.