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When to Plant Microgreens in USDA Zone 4b

Zone 4b Zone 4b April

Top priorities for Zone 4b gardeners in April

Here's what deserves your attention in Zone 4b this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost May 5
Avg. first frost October 6
  1. Sow microgreens where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Looking ahead to May
  • Transplants going out: microgreens
  • First harvests: microgreens
Send me my free Zone 4b Planting Guide →

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.

In Zone 4b, the average last spring frost is around May 1 and the first fall frost is around October 3, giving you a growing season of approximately 155 days.

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Zone 4b Moderate season
155 days
Last Spring Frost May 1
155 growing days
First Fall Frost October 3

Microgreens Planting Timeline — Zone 4b

Where Is USDA Zone 4b?

The map below highlights the states that contain Zone 4b. Click any state to see the Microgreens planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Microgreens Planting Calendar — Zone 4b

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 24 Apr 24 – May 15
Harvest May 8 May 8 – Jun 5
Fall Sowing July 11 Jul 11 – Jul 25

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

Month-by-Month Timeline

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

Free Zone 4b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4b with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

Days to Maturity

7–21 days

Soil pH

6 – 7

Zone Temperature Range

°F to °F average annual minimum

Growing Season

155 days (Zone average)

Planting Specifications

Planting Depth0.5 inches
Plant Spacing2 inches apart
Row Spacing6 inches between rows

Succession Planting Microgreens in Zone

30
successive plantings in Zone 's ~155-day season

Sow every 0.7 weeks for continuous harvest throughout the season.

Growing Tips for Microgreens in Zone

Zone has a short growing season (~155 days). Start Microgreens indoors early and use season-extension techniques like row covers and cold frames.

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.

Saving Microgreens Seeds

Recommended for Your Garden

🌱
Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

🧪
Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

🏷️
Garden Plant Markers $6-12

Keep your garden organized with durable, weather-resistant plant labels.

Frequently Asked Questions

When should I plant Microgreens in Zone 4b?

In Zone 4b, plan your Microgreens planting around the average last frost date of May 1. Start seeds indoors around March 20. Direct sow outdoors around April 24. Transplant seedlings around May 1.

Can Microgreens grow in Zone 4b?

Yes, Microgreens can grow well in Zone 4b, hardy in USDA zones 1a through 13b. Zone 4b has a growing season of approximately 155 days, which is sufficient for Microgreens (7-21 days to maturity).

When can I harvest Microgreens in Zone 4b?

In Zone 4b, expect to harvest Microgreens from May 8 – June 5. Microgreens takes 7-21 days from planting to harvest.

What is the last frost date for Zone 4b?

The average last spring frost in Zone 4b is around May 1, and the first fall frost is around October 3. This gives a growing season of approximately 155 days. These are 50% probability dates — actual frost dates vary year to year.

🌱

Your Free Printable Garden Planner

A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — 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.