Hello Hollis!

Great question! Culantro, is used a lot in Vietnamese or South East Asian cuisines, but did you know that they are mainly grown in Mexico?! You can defiantly find them at an Asian market, but if you can't find them at an Asian market you can try a Mexican Grocery Store. A substitute for culantro is cilantro, although they are not the same herb, they are in the same family of herbs. As for Rice Paddy Herb (Ngo Om), you can defiantly find them at any Asian market, but if you can't cumin can be a great substitute. Both cumin and rice paddy herb has an earthy tone to them which will brings out the same flavors in your dish.