Lavender is said to be tricky from seed, so I did a little experiment. Since lavender needs a long growing season to produce the flowers, they need to be started now in my area, but also require stratification (cool temps before sowing). Wintersowing is an option, but they probably won't germinate for at least a month.
I put 6 seeds in a DAMP paper-towel and stuck it in the freezer for 24 hours. After they were back up to room temp, I sowed them and put them under lights. The 1st seedling emerged in 3 days and the rest were up within 5 days. How cool is THAT!! The package advised chilling them in the fridge for 1 month, which would have needed to have been done a month ago to sow them now.