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When to Plant Borage in USDA Zone 4a

Zone 4a Zone 4a May

May in the garden — Zone 4a

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 13
Avg. first frost September 28
  1. Time to transplant borage

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Outdoor sowing time: borage

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

June prep starts now
  • Starting indoors: borage
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Borage is a self-seeding annual herb with star-shaped blue flowers that attract pollinators. Its leaves have a cucumber-like flavor and the flowers are edible.

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.

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

Borage 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 Borage planting schedule for that location.

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

Borage Planting Calendar — Zone 4a

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 29 Apr 29 – May 20
Harvest June 24 Jun 24 – Aug 12
Fall Sowing July 6 Jul 6 – Jul 20

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

Days to Maturity

50–60 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 Spacing8 inches apart
Row Spacing12 inches between rows

Succession Planting Borage in Zone

3
successive plantings in Zone 's ~145-day season

Sow every 5.7 weeks for continuous harvest throughout the season.

Growing Tips for Borage in Zone

Zone has a short growing season (~145 days). Start Borage indoors early and use season-extension techniques like row covers and cold frames.

Direct sow in spring as borage does not transplant well. Allow some plants to go to seed for next year. Young leaves are best; older leaves become bristly.

Companion Planting

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Saving Borage Seeds

Recommended for Your Garden

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Fabric Grow Bags $10-25

Breathable fabric pots that promote healthy root growth and prevent overwatering.

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Self-Watering Planters $15-40

Built-in reservoir keeps herbs and greens consistently watered with less effort.

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Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

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Frequently Asked Questions

When should I plant Borage in Zone 4a?

In Zone 4a, plan your Borage 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 April 29.

Can Borage grow in Zone 4a?

Yes, Borage can grow well in Zone 4a, hardy in USDA zones 3a through 11b. Zone 4a has a growing season of approximately 145 days, which is sufficient for Borage (50-60 days to maturity).

When can I harvest Borage in Zone 4a?

In Zone 4a, expect to harvest Borage from June 24 – August 12. Borage takes 50-60 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.

What should I plant next to Borage?

Good companion plants for Borage include Tomatoes, Squash Summer, Strawberries. These companions can help with pest control, pollination, and nutrient sharing.

🌱

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: May 2026.

Sources & credits

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