When to Plant Shiso in Pitkin County, CO
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.
Pitkin County, Colorado is in USDA Zone 4a. The average last spring frost is June 16 and the first fall frost is September 7, giving you a growing season of approximately 83 days.
At an elevation of 6,411 feet, Pitkin County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 82°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.
Pitkin County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.3
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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Shiso Planting Timeline — Pitkin County, CO
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 21 | Apr 21 – May 5 |
| Transplant Outdoors | July 7 | Jul 7 – Jul 21 |
| Direct Sow | June 23 | Jun 23 – Jul 14 |
| Harvest | September 1 | Sep 1 – Oct 27 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors |
| June | Direct Sow |
| July | Transplant Outdoors Direct Sow |
| August | — |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Partial Shade (3-6 hours)
Water
Moderate — regular watering
Days to Maturity
50–70 days
Soil pH
5.5 – 7
USDA Zone
Zone 4a
Growing Season
83 days
Growing Tips for Pitkin County
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
Level Up Your Garden
Shiso in Other Locations
Frequently Asked Questions
When should I plant Shiso in Pitkin County, CO?
Pitkin County is in Zone 4a with an average last frost of June 16. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pitkin County, CO?
Pitkin County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 16 and first fall frost is September 7.
Plan Your Garden with Confidence
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