When to plant Shiso in Howard County, IA
The best window to plant Shiso in Howard County, is May 11–June 1, when soil warms to 50°F. Last frost typically hits May 4; first frost October 5.
When to Plant Shiso in Howard County, IA
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.
Howard County, Iowa is in USDA Zone 4b. The average last spring frost is May 4 and the first fall frost is October 5, giving you a growing season of approximately 154 days.
At an elevation of 1,297 feet, Howard County receives approximately 39.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Shiso to ensure they mature before fall.
Howard County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Shiso Planting Timeline — Howard County, IA
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | May 25 | May 25 – Jun 8 |
| Direct Sow | May 11 | May 11 – Jun 1 |
| Harvest | July 20 | Jul 20 – Sep 14 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| 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
Moderate — regular watering
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.5–7 · Your soil: N/A
🗺️ USDA Zone
Zone 4b
📆 Growing Season
154 days in Howard County
Growing Tips for Howard 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
Check more plant combinations with our Companion Planting Checker →
Shiso in Other Locations
Frequently Asked Questions
When should I plant Shiso in Howard County, IA?
Howard County is in Zone 4b with an average last frost of May 4. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is Howard County, IA?
Howard County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is May 4 and first fall frost is October 5.
When should I plant Shiso in Howard County, IA?
In Howard County, IA, plant Shiso after the last frost (around May 4) and before the first frost (around October 5). Best results when soil holds above 50°F.
What growing zone is Howard County, IA for Shiso?
Howard County sits in USDA Zone 4b. Shiso grows reliably in zones 3a through 11b, so it's a good fit here.
Can Shiso grow in Howard County's climate?
Yes — Shiso grows well in Howard County's temperate climate. Howard County averages a 154-day frost-free season, with last frost around May 4 and first frost around October 5.
Your Howard County Garden Planner — Free
A 22-page printable planner built for Howard County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.