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When to Plant Mizuna in Portsmouth City, VA

Portsmouth City, Virginia Zone 8b May

May to-do list for Portsmouth City, Virginia

Each item below is timed to Portsmouth City, Virginia's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 22
Avg. first frost November 17
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 14 hrs
  1. Harvest mizuna as they ripen

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.

Portsmouth City, Virginia is in USDA Zone 8b. The average last spring frost is March 22 and the first fall frost is November 17, giving you a growing season of approximately 240 days.

At an elevation of 594 feet, Portsmouth City receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Mizuna during the growing season.

Portsmouth City, VA (Zone 8b) Long season
240 days
Last Spring Frost March 22
240 growing days
First Fall Frost November 17

Portsmouth City Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (175 days to spare)
Start indoors: Feb 9 Transplant: Mar 16 🍅 Harvest: Apr 20 – May 18
Recommended (50%) ✓ Fits season (177 days to spare)
Start indoors: Feb 15 Transplant: Mar 22 🍅 Harvest: Apr 26 – May 24
Safe Start (90%) ✓ Fits season (161 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Jun 25

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 Portsmouth City

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

Soil pH

Your soil pH (5.4–7.0) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Portsmouth City is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Mizuna.

How to Plant Mizuna

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

9
successive plantings in your 240-day season

Sow every 3.4 weeks. Last sowing by Oct 03 to harvest before frost.

For a dedicated fall crop, sow by Sep 08.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 577 gal / 100 sq ft

Monthly Watering Guide for Mizuna

Mizuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Mizuna Needs Rainfall You Supplement Action
Jan 3.4" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 4.3" 4.4" 0" ✅ Rainfall sufficient
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3" 1.3" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 4.3" 3" 1.3" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Portsmouth City). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mizuna 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.

Mizuna needs ~741 GDD — county provides 4,740 GDD Excellent fit

Mizuna Planting Timeline — Portsmouth City, VA

Mizuna Planting Calendar

Activity When Date Range
Start Indoors February 15 Feb 15 – Mar 1
Transplant Outdoors March 22 Mar 22 – Apr 5
Direct Sow March 8 Mar 8 – Mar 29
Harvest April 26 Apr 26 – May 24
Fall Sowing September 8 Sep 8 – Sep 22

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

30–45 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

240 days in Portsmouth City

Growing Tips for Mizuna in Portsmouth City

Direct sow Mizuna outdoors after March 22 in Portsmouth City when soil has warmed and frost danger has passed.

Your generous 240.0-day season in Portsmouth City allows multiple plantings of Mizuna. Sow every 15.0 days for continuous harvest.

Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mizuna in Portsmouth City, VA?

Portsmouth City is in Zone 8b with an average last frost of March 22. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Portsmouth City, VA?

Portsmouth City, Virginia is in USDA Hardiness Zone 8b. The average last spring frost is March 22 and first fall frost is November 17.

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Your Portsmouth City Garden Planner — Free

A 24-page printable planner built for Portsmouth City (Zone 8b). 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 Portsmouth City, VA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.