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When to plant Shiso in Philo, IL

Plant Shiso in Philo, when soil hits 50°F — usually April 21. Continue planting through May 12 for the spring crop.

When to Plant Shiso in Philo, IL

Champaign County, Illinois Zone 6a July

July in Champaign County, Illinois — your action list

July is a pivotal month for Champaign County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 14
Avg. first frost October 19
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Pick shiso

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Coming up in August — start thinking about
  • First harvests: shiso

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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.

Philo, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 19, giving you a growing season of approximately 188 days.

At an elevation of 1,215 feet, Champaign County receives approximately 38.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Shiso during the growing season.

Philo, IL (Zone 6a) Moderate season
188 days
Last Spring Frost April 14
188 growing days
First Fall Frost October 19

Philo Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Shiso Planting Risk Windows

Early Start (70% safe) ✓ Fits season (63 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jun 17 – Aug 12
Recommended (50%) ✓ Fits season (62 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 18
Safe Start (90%) ✓ Fits season (65 days to spare)
Start indoors: Mar 6 Transplant: May 8 🍅 Harvest: Jul 3 – Aug 28

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 Philo

How your county's soil matches Shiso's growing requirements.

Soil pH

Your soil pH (5.9–6.8) is within Shiso's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Champaign County is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.2%) — Shiso will thrive.

How to Plant Shiso

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Shiso

4
successive plantings in your 188-day season

Sow every 5.7 weeks. Last sowing by Aug 10 to harvest before frost.

Shiso Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 219 gal / 100 sq ft

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 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Champaign 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 needs ~915 GDD — county provides 2,867 GDD Excellent fit

Shiso Planting Timeline — Philo, IL

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 21 Apr 21 – May 12
Harvest June 23 Jun 23 – Aug 18

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

188 days in Champaign County

Growing Tips for Shiso in Philo

Direct sow Shiso outdoors after April 14 in Champaign County when soil has warmed and frost danger has passed.

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 →

When should I plant Shiso in Philo, IL?

In Philo, IL, plant Shiso after the last frost (around April 14) and before the first frost (around October 19). Best results when soil holds above 50°F.

What growing zone is Philo, IL for Shiso?

Philo sits in USDA Zone 6a. Shiso grows reliably in zones 3a through 11b, so it's a good fit here.

Can Shiso grow in Philo's climate?

Yes — Shiso grows well in Philo's temperate climate. Philo averages a 188-day frost-free season, with last frost around April 14 and first frost around October 19.

🌱

Your Champaign County Garden Planner — Free

A 22-page printable planner built for Champaign County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Champaign County, IL. Local conditions may vary. Last updated: July 2026.