When to Plant Shiso in Flagler County, FL
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.
Flagler County, Florida is in USDA Zone 9a. The average last spring frost is February 5 and the first fall frost is December 17, giving you a growing season of approximately 315 days.
At an elevation of 134 feet, Flagler County receives approximately 54.2 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Shiso may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Shiso will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Shiso root diseases.
Flagler County Soil Profile
Soil Type
Sand
Soil pH
5.1-5.7
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 Flagler County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (5.1–5.7) is more acidic than Shiso prefers (5.5–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in Flagler County warms quickly in spring but drains fast. Shiso will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Shiso.
Organic Matter
Organic matter is low (1.6%). Add 2-3 inches of compost before planting Shiso.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Oct 08 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 | — | 2.7" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Mar | 4.3" | 3" | 1.3" | 💧 Light watering |
| Apr | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| May | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jun | 4.3" | 8.8" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.4" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.9" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Dec | 4.3" | 2.5" | 1.8" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in Flagler 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 — Flagler County, FL
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 25 | Dec 25 – Jan 8 |
| Transplant Outdoors | February 12 | Feb 12 – Feb 26 |
| Direct Sow | February 12 | Feb 12 – Mar 5 |
| Harvest | April 9 | Apr 9 – Jun 4 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Transplant Outdoors Direct Sow |
| March | Direct Sow |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | Start Indoors |
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_acidic
🗺️ USDA Zone
Zone 9a
📆 Growing Season
315 days in Flagler County
Growing Tips for Shiso in Flagler County
Direct sow Shiso outdoors after February 05 in Flagler County when soil has warmed and frost danger has passed.
Sandy soil in Flagler County dries quickly — mulch Shiso with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 99°F in Flagler County, provide afternoon shade for Shiso and water deeply in the morning.
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 Flagler County, FL?
Flagler County is in Zone 9a with an average last frost of February 5. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Flagler County, FL?
Flagler County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 5 and first fall frost is December 17.
Plan Your Garden with Confidence
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