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When to plant Shiso in Viola, DE

Spring Shiso in Viola goes in April 9–April 30, once nighttime temps stop dipping near freezing.

When to Plant Shiso in Viola, DE

Kent County, Delaware Zone 7b July

Your July gardening checklist

We've pulled the most time-sensitive tasks for Kent County, Delaware this July and put them front and centre. Tackle them in order.

Avg. last frost April 2
Avg. first frost November 4
Soil temp (4") 87°F
Watering Low
Pest pressure High
Daylight 14.5 hrs
  1. Start harvesting shiso

    If you can't use it all right away, check the food-preservation section of your planner.

Looking ahead to August
  • 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.

Viola, Delaware is in USDA Zone 7b. The average last spring frost is April 2 and the first fall frost is November 4, giving you a growing season of approximately 216 days.

At an elevation of 128 feet, Kent County receives approximately 47.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Shiso during the growing season.

Viola, DE (Zone 7b) Long season
216 days
Last Spring Frost April 2
216 growing days
First Fall Frost November 4

Viola Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Shiso Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Start indoors: Feb 7 Transplant: Apr 11 🍅 Harvest: Jun 6 – Aug 1
Recommended (50%) ✓ Fits season (90 days to spare)
Start indoors: Feb 12 Transplant: Apr 16 🍅 Harvest: Jun 11 – Aug 6
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Feb 28 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 22

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 Viola

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

Soil pH

Your soil pH (5.8–6.8) is within Shiso's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Shiso.

How to Plant Shiso

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

Succession Planting Shiso

5
successive plantings in your 216-day season

Sow every 5.7 weeks. Last sowing by Aug 26 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 132 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 4" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 5.6" 0" ✅ Rainfall sufficient
Aug 4.3" 4.9" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 4" 0.3" 💧 Light watering
Nov 4.3" 3.5" 0.8" 💧 Light watering
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Kent 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 ~960 GDD — county provides 3,456 GDD Excellent fit

Shiso Planting Timeline — Viola, DE

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 9 Apr 9 – Apr 30
Harvest June 11 Jun 11 – Aug 6

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May
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 7b

📆 Growing Season

216 days in Kent County

Growing Tips for Shiso in Viola

Direct sow Shiso outdoors after April 02 in Kent 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 Viola, DE?

In Viola, DE, plant Shiso after the last frost (around April 2) and before the first frost (around November 4). Best results when soil holds above 50°F.

What growing zone is Viola, DE for Shiso?

Viola sits in USDA Zone 7b. Shiso grows reliably in zones 3a through 11b, so it's a good fit here.

Can Shiso grow in Viola's climate?

Yes — Shiso grows well in Viola's temperate climate. Viola averages a 216-day frost-free season, with last frost around April 2 and first frost around November 4.

🌱

Your Kent County Garden Planner — Free

A 22-page printable planner built for Kent County (Zone 7b). 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 Kent County, DE. Local conditions may vary. Last updated: July 2026.