Answer: My sources indicate that Stevia is self-incompatible, which means it must be cross-pollinated in order to produce viable seeds. You must have more than one Stevia plant in your garden for either (or both) plants to produce viable seeds. If you have only one plant, you'll never get seeds that sprout.
Try planting two Stevia plants in your garden this year and collecting the seeds after the seed pods turn a tannish brown but before they burst open and spill their seeds on the ground. When you get a good collection of seeds, sow them on top of moistened seed starting mix (they need light to germinate) and cover the pots or trays with plastic wrap to help hold in the moisture. Viable seeds will sprout in less than 14 days when kept warm (70F). As soon as the seeds sprout, remove the plastic wrap and place the pots or trays under a source of bright light. Keep the potting soil moist but not soggy wet.
Best wishes with your new little seedlings!
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