Direct seed 6 weeks before last frost. Seedlings won't be damaged by light frost. They may be started indoors 8 weeks prior to last frost in deep cell container as they have a taproot and do not like being disturbed. In warmer climate, you can sow seeds in fall.
Personally, I had success with "winter sowing" method in a milk jug!
Sweet Pea 'Turquoise Lagoon'
Sowing & Growing
Pansies/Violas like cool weather. You can start pansies/violas seeds indoors in trays 8-12 weeks before you intend to transplant outside. They can withstand a light frost, so cold-climate gardeners can pick a transplant date that is about 2 weeks before the last frost. Alternatively, you can start seeds in summer and transplant in fall.
Personally, I had success with "winter sowing" method in a milk jug!