Bonnie has seeds, Home Depot carries Bonnie seeds in my area. EBay and Etsy have sellers for seeds. Shipping should be minimal. Amazon lists some seeds. Walmart is a possibility, too.

Here is the Bonnie plant finder tool. Just put in your zip code.

http://find.bonnieplants.com/

Hope that helps.

Check Asian grocery stores around you. Here in Seattle most of them sell Asian vegetable seeds, including culantro.

I'm growing some in a garden box. They're coming up nicely.