Plant Cilantro in Zone 3b
Seed-starting, transplant & harvest dates for USDA Zone 3b
Zone 3b averages 128 frost-free days, running from a last spring frost around May 13 to a first fall frost around September 18. Cilantro needs roughly 45 days from planting out to first harvest, so it uses about 35 percent of that window. Cilantro is a half-hardy crop, which is what decides where in the window it belongs.
Cilantro handles cold soil, so there is no reason to wait for the frost date. Direct sow around Apr 29, roughly 2 weeks before the Zone 3b last frost, as soon as the ground is workable. Sowing at the last frost instead costs you the coolest and best part of the season. At 45 days to harvest, a 128-day Zone 3b season has room for about 2 sowings, so stagger them rather than planting everything at once.
Planting cilantro for a fall harvest in Zone 3b
Yes. Sow cilantro by August 4 in Zone 3b. That is 45 days before the average first frost, which covers the 45 days to maturity plus about two weeks for the slower growth that comes with shortening days, minus the roughly 14 days cilantro keeps going once light frost arrives.
Cilantro bolts within weeks in summer heat and is far more productive as a fall crop, and in mild zones it runs right through winter.
Fall dates are counted backward from the Zone 3b average first frost, not forward from a sowing date. See the fall planting calendar by zone for the full method.
Spring vs fall cilantro in Zone 3b
| Planting | Sow or start | In the ground | Harvest |
|---|---|---|---|
| Spring | Apr 29 | Apr 29 | Jun 13 |
| Fall | by Aug 4 | Aug 4 | Sep 18 |
Cilantro in nearby zones
Further reading on cilantro
- Cold frame gardening by zone
How a cold frame keeps cilantro producing into winter, and when to sow it.
- Growing herbs indoors over winter
Keeping cilantro going on a windowsill or under lights once frost ends it outside.
- Winter sowing guide
Sowing cilantro outdoors in jugs in late winter, with no lights.
Other crops in Zone 3b
Frequently asked questions
When should I start cilantro in Zone 3b?
Direct sow outdoors around Apr 29.
Can I direct sow cilantro in Zone 3b?
Yes, direct sow around Apr 29.
Can I plant cilantro in the fall in Zone 3b?
Yes. Sow cilantro by August 4 in Zone 3b. That is 45 days before the average first frost, which covers the 45 days to maturity plus about two weeks for the slower growth that comes with shortening days, minus the roughly 14 days cilantro keeps going once light frost arrives.
Will cilantro survive frost in Zone 3b?
Cilantro is a half-hardy crop and keeps going roughly 14 days past the first light frost in Zone 3b. A row cover or a straw mulch buys more.
How many plantings of cilantro fit in a Zone 3b season?
About 2. Zone 3b averages 128 frost-free days and cilantro needs roughly 45 days plus a couple of weeks of turnaround, so sowing every 30 days keeps a supply coming.