When to Plant Cilantro in Colorado (2026 Guide)

Cilantro is a delightful herb used in various culinary dishes, known for its vibrant flavor and aromatic qualities. In Colorado, understanding when to plant cilantro is essential for a successful and flavorful harvest. Based on the median frost dates, zones range from an approximate last spring frost of May 5 in Zone 5b to April 25 in Zone 6a.

For gardeners in Colorado, the planting schedule can vary significantly between regions. Those in Arvada and Boulder (Zone 5b) will want to consider the median last frost date of May 5, while those in Grand Junction (Zone 6a) can benefit from a more extended frost-free season with a last frost date of April 25. This knowledge ensures that you give your cilantro the best chance at thriving.

To maximize your cilantro crop, it's crucial to direct sow the seeds, as cilantro has a taproot and does not transplant well. By understanding the best practices and timing for planting cilantro across different zones, you can enjoy fresh herbs for your culinary endeavors. Remember, cilantro bolts quickly during the warmer months, so early planting is key.

Planting Schedule by USDA Zone in Colorado

Zone	Indoor start	Transplant out	Direct sow	Harvest
Zone 5b	Not recommended — direct sow only	Not recommended — direct sow only	Direct sow from April 10 – May 5, ~2 weeks after the last frost date	Harvest from May 25 – September 1, ~6–8 weeks after sowing
Zone 5a	Not recommended — direct sow only	Not recommended — direct sow only	Direct sow from April 20 – May 17, ~2 weeks after the last frost date	Harvest from June 1 – September 1, ~6–8 weeks after sowing
Zone 6a	Not recommended — direct sow only	Not recommended — direct sow only	Direct sow from March 25 – April 25, ~2 weeks after the last frost date	Harvest from May 10 – October 16, ~6–8 weeks after sowing

Cilantro Planting Windows in Colorado

Indoor start: Not applicable, as cilantro should be directly sown outdoors.
Transplant outdoors: Not applicable, as cilantro should only be directly sown outdoors.
Harvest: For Colorado's cilantro, expect to begin harvesting approximately 6–8 weeks after sowing, typically from late May until October.

Common Mistakes Growing Cilantro in Colorado

Many Colorado gardeners attempt to start cilantro indoors, not realizing it is a taproot herb that does not transplant well. This often leads to stunted plants. Always direct sow your seeds to ensure success.
Some gardeners in Colorado plant cilantro too late in the spring. Because cilantro bolts quickly in the heat, missing the optimal planting period can result in a short harvest window.
In Colorado, heavy clay or alkaline soil is common, which can impede healthy cilantro growth. Ensure that your soil is well-drained and enriched with compost to provide the nutrients cilantro needs to thrive.
Gardeners in higher elevations of Colorado may encounter frost pockets, which can damage young cilantro plants. Keep an eye on local frost advisories and be prepared to protect your plants with covers if needed.
Companion planting can be mismanaged; some Colorado gardeners place cilantro too close to dill, resulting in flavor loss due to cross-pollination. Keep these two herbs separated by at least 3–4 feet if you intend to save seeds.

Frequently Asked Questions

What if I'm in a cold pocket of Colorado?

If you are located in a cold pocket, pay close attention to local frost dates, as they may be later than the general zone dates. Utilize protective covers to shield young cilantro plants from late frosts.

Can I still plant cilantro in May?

Yes, you can plant cilantro in May, especially if you're in Zone 5a or 5b. Aim to direct sow the seeds after the last frost, ideally by mid-May to ensure successful germination.

How can I extend my cilantro harvest?

To extend your cilantro harvest, practice succession planting by sowing seeds every 2–3 weeks throughout the cooler months. Incorporating slow-bolting varieties will also help prolong the harvesting period before the heat sets in.

Is cilantro easy to grow in Colorado?

Cilantro can be easy to grow in Colorado if you follow the appropriate planting times and techniques. Direct sowing, paying attention to temperatures, and considering the growing season length are essential for success.

What should I do if my cilantro bolts?

If your cilantro bolts, it's best to let it flower and set seed rather than pulling it up. This helps attract beneficial insects that can improve your garden's ecosystem and ensures volunteer plants next season.

Keep Learning

Typical fall sowing window for Cilantro in Colorado: July 12 – August 2.