When to Plant Shiso in Grimes County, TX
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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.
Grimes County, Texas is in USDA Zone 9a. The average last spring frost is February 25 and the first fall frost is December 1, giving you a growing season of approximately 279 days.
At an elevation of 33 feet, Grimes County receives approximately 65.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 91°F, providing good warmth for Shiso during the growing season. 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.
Grimes County Soil Profile
Soil Type
Sandy Loam
Soil pH
5.8-6.5
Drainage
Well Drained
Shiso 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 Grimes County
How your county's soil matches Shiso's growing requirements.
Soil pH
Your soil pH (5.8–6.5) is within Shiso's preferred range (5.5–7.0).
Soil Texture
Sandy soil in Grimes 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 (1.7%). Add 2-3 inches of compost before planting Shiso.
How to Plant Shiso
Succession Planting Shiso
Sow every 5.7 weeks. Last sowing by Sep 22 to harvest before frost.
Shiso Water Budget
Water stress score is 6/10 — 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 | — | 1.9" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Mar | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 6" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 9.9" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 9.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 8.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 8.3" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.6" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Nov | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Dec | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in Grimes 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 — Grimes County, TX
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 14 | Jan 14 – Jan 28 |
| Transplant Outdoors | March 4 | Mar 4 – Mar 18 |
| Direct Sow | March 4 | Mar 4 – Mar 25 |
| Harvest | April 29 | Apr 29 – Jun 24 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| 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: ideal
🗺️ USDA Zone
Zone 9a
📆 Growing Season
279 days in Grimes County
Growing Tips for Shiso in Grimes County
Direct sow Shiso outdoors after February 25 in Grimes County when soil has warmed and frost danger has passed.
Sandy soil in Grimes County dries quickly — mulch Shiso with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
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 Grimes County, TX?
Grimes County is in Zone 9a with an average last frost of February 25. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grimes County, TX?
Grimes County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 25 and first fall frost is December 1.
Your Grimes County Garden Planner — Free
A 22-page printable planner built for Grimes County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.