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When to Plant Mizuna in Herkimer County, NY

Herkimer County, New York Zone 5b May

Your May game plan for Herkimer County, New York

We've pulled the most time-sensitive tasks for Herkimer County, New York this May and put them front and centre. Tackle them in order.

Avg. last frost May 15
Avg. first frost September 30
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Set out mizuna seedlings

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Plant mizuna from seed, right in the garden

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

June will be here before you know it — start on
  • Starting indoors: mizuna
  • First harvests: mizuna

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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.

Herkimer County, New York is in USDA Zone 5b. The average last spring frost is May 15 and the first fall frost is September 30, giving you a growing season of approximately 138 days.

At an elevation of 160 feet, Herkimer County receives approximately 48.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Mizuna to ensure they mature before fall.

Herkimer County, NY (Zone 5b) Short season
138 days
Last Spring Frost May 15
138 growing days
First Fall Frost September 30

Herkimer County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jun 15 – Jul 13
Recommended (50%) ✓ Fits season (75 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Jun 19 – Jul 17
Safe Start (90%) ✓ Fits season (73 days to spare)
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Jul 5 – Aug 2

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 Herkimer County

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

Soil pH

Your soil pH (5.1–6.4) is more acidic than Mizuna prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Mizuna.

Organic Matter

Organic matter is moderate (3.7%). 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

5
successive plantings in your 138-day season

Sow every 3.4 weeks. Last sowing by Aug 16 to harvest before frost.

For a dedicated fall crop, sow by Jul 22.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 3.7" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.7" 0" ❄️ Dormant
May 4.3" 5.1" 0" ✅ Rainfall sufficient
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 3.5" 0" ❄️ Dormant
Nov 3.5" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Herkimer County). 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 ~431 GDD — county provides 1,587 GDD Excellent fit

Mizuna Planting Timeline — Herkimer County, NY

Mizuna Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 1 May 1 – May 22
Harvest June 19 Jun 19 – Jul 17
Fall Sowing July 22 Jul 22 – Aug 5

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

30–45 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5b

📆 Growing Season

138 days in Herkimer County

Growing Tips for Mizuna in Herkimer County

Direct sow Mizuna outdoors after May 15 in Herkimer County when soil has warmed and frost danger has passed.

Your generous 138.0-day season in Herkimer County 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 Herkimer County, NY?

Herkimer County is in Zone 5b with an average last frost of May 15. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Herkimer County, NY?

Herkimer County, New York is in USDA Hardiness Zone 5b. The average last spring frost is May 15 and first fall frost is September 30.

🌱

Your Herkimer County Garden Planner — Free

A 24-page printable planner built for Herkimer County (Zone 5b). 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 Herkimer County, NY. 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.