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When to Plant Cilantro in USDA Zone 3b

Zone 3b Zone 3b May

Zone 3b gardeners: here's your May plan

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 16
Avg. first frost September 22
  1. Time to transplant cilantro

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Put cilantro seeds straight in the ground

    These tolerate cool soil, so you're not gambling by sowing now.

Looking ahead to June
  • Starting indoors: cilantro
  • First harvests: cilantro
  • Fall sowing: cilantro
Download your personalised Zone 3b planting plan →
Cilantro

Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

In Zone 3b, the average last spring frost is around May 10 and the first fall frost is around September 22, giving you a growing season of approximately 135 days.

Zone 3b Short season
135 days
Last Spring Frost May 10
135 growing days
First Fall Frost September 22

Cilantro Planting Timeline — Zone 3b

Where Is USDA Zone 3b?

The map below highlights the states that contain Zone 3b. Click any state to see the Cilantro planting schedule for that location.

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

Cilantro Planting Calendar — Zone 3b

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 3 May 3 – May 17
Direct Sow May 3 May 3 – May 24
Harvest June 14 Jun 14 – Aug 16
Fall Sowing June 30 Jun 30 – Jul 14

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

Month-by-Month Timeline

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

Free Zone 3b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 3b with start dates, transplant windows, and harvest times.

Instant PDF download. No spam, unsubscribe any time.

Growing Conditions

Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Moderate — regular watering

Days to Maturity

40–60 days

Soil pH

6 – 7

Zone Temperature Range

°F to °F average annual minimum

Growing Season

135 days (Zone average)

Planting Specifications

Planting Depth0.5 inches
Plant Spacing8 inches apart
Row Spacing12 inches between rows

Succession Planting Cilantro in Zone

3
successive plantings in Zone 's ~135-day season

Sow every 4.6 weeks for continuous harvest throughout the season.

Growing Tips for Cilantro in Zone

Zone has a short growing season (~135 days). Start Cilantro indoors early and use season-extension techniques like row covers and cold frames.

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
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Saving Cilantro Seeds

Recommended for Your Garden

🪴
Fabric Grow Bags $10-25

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

🏺
Self-Watering Planters $15-40

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

🌱
Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

Related Plants

Frequently Asked Questions

When should I plant Cilantro in Zone 3b?

In Zone 3b, plan your Cilantro planting around the average last frost date of May 10. Start seeds indoors around March 29. Direct sow outdoors around May 3. Transplant seedlings around May 3.

Can Cilantro grow in Zone 3b?

Yes, Cilantro can grow well in Zone 3b, hardy in USDA zones 2a through 11b. Zone 3b has a growing season of approximately 135 days, which is sufficient for Cilantro (40-60 days to maturity).

When can I harvest Cilantro in Zone 3b?

In Zone 3b, expect to harvest Cilantro from June 14 – August 16. Cilantro takes 40-60 days from planting to harvest.

What is the last frost date for Zone 3b?

The average last spring frost in Zone 3b is around May 10, and the first fall frost is around September 22. This gives a growing season of approximately 135 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Cilantro?

Good companion plants for Cilantro include Tomatoes, Peppers, Spinach. 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.

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: May 2026.

Sources & credits

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