Hi, I got a leaflet with my seeds,it says:
STEVIA
Stevia rebaudiana
Perennial Herb USDA Growing Zone 9+ that is warm!
Grow as annual other zones
Germination 7-14 days
Sowing Notes.
Indoor planting method.Start seeds 6-8 weeks befor last frost date.
Sow shallowly in a well drained soil mix in flats at a temperature of 68-75f.
Transplant to 3" pots when seedlings rae large enough to handle.Do not over water. For bushier plants,pich back the growing tips every few weks for the first 1-2 months after germination.
Outdoor planting: Stevia generally does not tolerate temperatures below 45f.After all danger off frost has passed.transplant outside 12 " apart.Stevia is also an idieal plant to grow in containers as a houseplant,or in the greenhouse.For container growing,choose a pot that is at least 14" accross and provide soil that is well drained.Maintain even soil moisture and provide shade in extreme heat.
XX Jeannine