When to Plant Shiso in Ouray County, CO
What to do in May
Welcome to May in Zone 5b. These are the moves that will have the biggest impact on your growing season.
Get ahead of June
- Direct-sowing: 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.
Ouray County, Colorado is in USDA Zone 5b. The average last spring frost is June 18 and the first fall frost is September 10, giving you a growing season of approximately 84 days.
At an elevation of 7,449 feet, Ouray County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Shiso during the growing season. With low rainfall, drip irrigation is essential for growing Shiso successfully. Mulch heavily to conserve soil moisture.
Ouray County Soil Profile
Soil Type
Loam
Soil pH
6.4-8.3
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.
Soil Compatibility in Ouray County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (6.4–8.3) is more alkaline than Shiso prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Ouray County is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Shiso.
How to Plant Shiso
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 | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 0.7" | 0" | ❄️ Dormant |
| Mar | — | 1" | 0" | ❄️ Dormant |
| Apr | — | 1.4" | 0" | ❄️ Dormant |
| May | — | 1.3" | 0" | ❄️ Dormant |
| Jun | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Jul | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Aug | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Sep | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Oct | — | 1" | 0" | ❄️ Dormant |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Ouray 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 — Ouray County, CO
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 30 | Apr 30 – May 14 |
| Transplant Outdoors | July 2 | Jul 2 – Jul 16 |
| Direct Sow | June 25 | Jun 25 – Jul 16 |
| Harvest | August 27 | Aug 27 – Oct 22 |
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 | 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: too_alkaline
🗺️ USDA Zone
Zone 5b
📆 Growing Season
84 days in Ouray County
Growing Tips for Shiso in Ouray County
Direct sow Shiso outdoors after June 18 in Ouray County when soil has warmed and frost danger has passed.
Ouray County receives only 13" 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 Ouray County, CO?
Ouray County is in Zone 5b with an average last frost of June 18. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Ouray County, CO?
Ouray County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 18 and first fall frost is September 10.
Your Ouray County Garden Planner — Free
A 24-page printable planner built for Ouray County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.