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When to plant Microgreens in Pennington County, MN

Plant Microgreens in Pennington County after May 10; the prime window is May 3–May 24. A second sowing from July 8 to July 22 extends the harvest into fall.

When to Plant Microgreens in Pennington County, MN

Pennington County, Minnesota Zone 3b July

Your July gardening checklist

Your Pennington County, Minnesota garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.

Avg. last frost May 10
Avg. first frost September 30
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 15.5 hrs
  1. Sow microgreens for an autumn harvest

    Count back from your first frost (September 30) — these need to mature before the cold arrives.

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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.

Pennington County, Minnesota is in USDA Zone 3b. The average last spring frost is May 10 and the first fall frost is September 30, giving you a growing season of approximately 143 days.

At an elevation of 854 feet, Pennington County receives approximately 35.1 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.

Pennington County, MN (Zone 3b) Short season
143 days
Last Spring Frost May 10
143 growing days
First Fall Frost September 30

Pennington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.1

Drainage

Well Drained

Microgreens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (110 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: May 9 – Jun 6
Recommended (50%) ✓ Fits season (108 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: May 17 – Jun 14
Safe Start (90%) ✓ Fits season (110 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: May 29 – Jun 26

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 Pennington County

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

Soil pH

Your soil pH (5.9–7.1) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.9%) — Microgreens will thrive.

How to Plant Microgreens

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

28
successive plantings in your 143-day season

Sow every 0.7 weeks. Last sowing by Sep 09 to harvest before frost.

For a dedicated fall crop, sow by Jul 08.

Microgreens Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/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 1.3" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 2.9" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Pennington 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 1,537 GDD Excellent fit

Microgreens Planting Timeline — Pennington County, MN

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 3 May 3 – May 24
Harvest May 17 May 17 – Jun 14
Fall Sowing July 8 Jul 8 – Jul 22

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

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 3b

📆 Growing Season

143 days in Pennington County

Growing Tips for Microgreens in Pennington County

Direct sow Microgreens outdoors after May 10 in Pennington County when soil has warmed and frost danger has passed.

Your generous 143.0-day season in Pennington 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 Pennington County, MN?

Pennington County is in Zone 3b with an average last frost of May 10. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pennington County, MN?

Pennington County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 10 and first fall frost is September 30.

When should I plant Microgreens in Pennington County, MN?

In Pennington County, MN, plant Microgreens after the last frost (around May 10) and before the first frost (around September 30). Best results when soil holds above 50°F.

What growing zone is Pennington County, MN for Microgreens?

Pennington County sits in USDA Zone 3b. Microgreens grows reliably in zones 1a through 13b, so it's a good fit here.

Can Microgreens grow in Pennington County's climate?

Yes — Microgreens grows well in Pennington County's temperate climate. Pennington County averages a 143-day frost-free season, with last frost around May 10 and first frost around September 30.

🌱

Your Pennington County Garden Planner — Free

A 22-page printable planner built for Pennington County (Zone 3b). 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 Pennington County, MN. Local conditions may vary. Last updated: July 2026.

Sources & credits

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