Blog

When to plant Microgreens in Keweenaw County County,

Keweenaw County County sits in USDA Zone 5b. Plant Microgreens between May 5 (after last frost on May 19) and May 26. A second sowing from July 23 to August 6 extends the harvest into fall.

When to Plant Microgreens in Keweenaw County, MI

Keweenaw County, Michigan Zone 5b June

June in Keweenaw County, Michigan — your action list

Welcome to June in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 19
Avg. first frost October 1
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.7 hrs
  1. Begin indoor sowing: microgreens

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. It's harvest week for microgreens

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

July will be here before you know it — start on
  • Fall sowing: microgreens

Instant PDF download. No spam, unsubscribe any time.

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.

Keweenaw County, Michigan is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.

At an elevation of 1,035 feet, Keweenaw County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Microgreens to ensure they mature before fall.

Keweenaw County, MI (Zone 5b) Short season
135 days
Last Spring Frost May 19
135 growing days
First Fall Frost October 1
Share this guide:

Keweenaw County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Microgreens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (100 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: May 22 – Jun 19
Recommended (50%) ✓ Fits season (100 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: May 26 – Jun 23
Safe Start (90%) ✓ Fits season (99 days to spare)
Start indoors: Apr 30 Transplant: Jun 4 🍅 Harvest: Jun 11 – Jul 9

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 Keweenaw County

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

Soil pH

Your soil pH (6.1–6.9) is within Microgreens's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — 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

26
successive plantings in your 135-day season

Sow every 0.7 weeks. Last sowing by Sep 10 to harvest before frost.

For a dedicated fall crop, sow by Jul 23.

Microgreens Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.7" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Keweenaw 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 ~150 GDD — county provides 1,451 GDD Excellent fit

Microgreens Planting Timeline — Keweenaw County, MI

Microgreens Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 – Apr 28
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 5 May 5 – May 26
Harvest May 26 May 26 – Jun 23
Fall Sowing July 23 Jul 23 – Aug 6

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

135 days in Keweenaw County

Growing Tips for Microgreens in Keweenaw County

Direct sow Microgreens outdoors after May 19 in Keweenaw County when soil has warmed and frost danger has passed.

Your generous 135.0-day season in Keweenaw 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 Keweenaw County, MI?

Keweenaw County is in Zone 5b with an average last frost of May 19. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Keweenaw County, MI?

Keweenaw County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 19 and first fall frost is October 1.

When should I plant Microgreens in Keweenaw County, ?

In Keweenaw County, , plant Microgreens after the last frost (around May 19) and before the first frost (around October 1). Best results when soil holds above 50°F.

What growing zone is Keweenaw County, for Microgreens?

Keweenaw County sits in USDA Zone 5b. Microgreens grows reliably in zones 1a through 13b, so it's a good fit here.

Can Microgreens grow in Keweenaw County's climate?

Yes — Microgreens grows well in Keweenaw County's temperate climate. Keweenaw County averages a 135-day frost-free season, with last frost around May 19 and first frost around October 1.

🌱

Your Keweenaw County Garden Planner — Free

A 22-page printable planner built for Keweenaw 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.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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