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When to Plant Microgreens in USDA Zone 4a

Zone 4a Zone 4a April

April in the garden — Zone 4a

Your Zone 4a garden is entering a new phase. Here's what's on the schedule for April and why each task matters now.

Avg. last frost May 13
Avg. first frost September 29
Before May arrives, get these ready
  • Transplants going out: microgreens
  • Direct-sowing: microgreens
  • 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.

In Zone 4a, the average last spring frost is around May 6 and the first fall frost is around September 28, giving you a growing season of approximately 145 days.

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Zone 4a Short season
145 days
Last Spring Frost May 6
145 growing days
First Fall Frost September 28

Microgreens Planting Timeline — Zone 4a

Where Is USDA Zone 4a?

The map below highlights the states that contain Zone 4a. 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 4a

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest May 13 May 13 – Jun 10
Fall Sowing July 6 Jul 6 – Jul 20

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 4a Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4a 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

145 days (Zone average)

Planting Specifications

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

Succession Planting Microgreens in Zone

28
successive plantings in Zone 's ~145-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 (~145 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 4a?

In Zone 4a, plan your Microgreens planting around the average last frost date of May 6. Start seeds indoors around March 25. Direct sow outdoors around April 29. Transplant seedlings around May 6.

Can Microgreens grow in Zone 4a?

Yes, Microgreens can grow well in Zone 4a, hardy in USDA zones 1a through 13b. Zone 4a has a growing season of approximately 145 days, which is sufficient for Microgreens (7-21 days to maturity).

When can I harvest Microgreens in Zone 4a?

In Zone 4a, expect to harvest Microgreens from May 13 – June 10. Microgreens takes 7-21 days from planting to harvest.

What is the last frost date for Zone 4a?

The average last spring frost in Zone 4a is around May 6, and the first fall frost is around September 28. This gives a growing season of approximately 145 days. These are 50% probability dates — actual frost dates vary year to year.

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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.

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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.