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When to Plant Microgreens in St. Joseph County, MI

St. Joseph County, Michigan Zone 5b April

This month in St. Joseph County, Michigan

A quick April briefing for St. Joseph County, Michigan gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 28
Avg. first frost October 16
Soil temp (4") 45°F
Watering Moderate
Pest pressure Low
Daylight 13.1 hrs
  1. Time to transplant microgreens

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Sow microgreens where they'll grow

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

Looking ahead to May
  • First harvests: microgreens

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

St. Joseph County, Michigan is in USDA Zone 5b. The average last spring frost is April 28 and the first fall frost is October 16, giving you a growing season of approximately 171 days.

At an elevation of 564 feet, St. Joseph County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Microgreens to ensure they mature before fall.

St. Joseph County, MI (Zone 5b) Moderate season
171 days
Last Spring Frost April 28
171 growing days
First Fall Frost October 16

St. Joseph County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (130 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: May 3 – May 31
Recommended (50%) ✓ Fits season (136 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: May 5 – Jun 2
Safe Start (90%) ✓ Fits season (130 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: May 22 – Jun 19

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 St. Joseph County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) — Microgreens will thrive.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Microgreens

33
successive plantings in your 171-day season

Sow every 0.7 weeks. Last sowing by Sep 25 to harvest before frost.

For a dedicated fall crop, sow by Aug 07.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 45 gal / 100 sq ft

Monthly Watering Guide for Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in St. Joseph County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Microgreens 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.

Microgreens needs ~182 GDD — county provides 2,223 GDD Excellent fit

Microgreens Planting Timeline — St. Joseph County, MI

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 – Apr 7
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 14 Apr 14 – May 5
Harvest May 5 May 5 – Jun 2
Fall Sowing August 7 Aug 7 – Aug 21

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

171 days in St. Joseph County

Growing Tips for Microgreens in St. Joseph County

Direct sow Microgreens outdoors after April 28 in St. Joseph County when soil has warmed and frost danger has passed.

Your generous 171.0-day season in St. Joseph County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in St. Joseph County, MI?

St. Joseph County is in Zone 5b with an average last frost of April 28. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Joseph County, MI?

St. Joseph County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is April 28 and first fall frost is October 16.

🌱

Your St. Joseph County Garden Planner — Free

A 24-page printable planner built for St. Joseph 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 St. Joseph County, MI. Local conditions may vary. Last updated: April 2026.

Sources & credits

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