Toothache plant (Acmella oleracea) contains a compound called spilanthol, which is responsible for the strong tingling and numbing sensation the flowers produce when chewed. This same compound is why the plant has traditionally been used to ease mouth pain and relieve dry mouth.
Fortunately for gardeners, toothache plant is easy to grow from seed, especially when you start with high-quality heirloom seeds.
Toothache plant seeds need warmth, light, and moisture to germinate. Wait until the soil is around 70ºF to sow seeds outdoors, or start seeds indoors with a heat mat. You can start seeds indoors 3-4 weeks before planting outdoors. Press seeds into the soil, but don’t bury them as they need light to germinate.