Sierra Mist is generally regarded as a tender plant, so remember to wait until your soil is warm and the night time temperature is well above freezing before moving outside.
Growing Sierra Mist from seed
By our calculations, you should look at sowing Sierra Mist about 91 days before your last frost date.
Transplanting Sierra Mist
Sierra Mist is tender, so ensure you wait until all danger of frost has passed in your area before considering planting outside.