Sow indoors 6-8 weeks before last frost , or direct sow 2 weeks before last frost.
If starting indoors, just cover the seeds with vermiculite and provide a soil temperature of 21-25°C (70-75°F). Seeds should sprout in 4-14 days at that temperature.

https://www.westcoastseeds.com/blogs/how-to-grow/grow-marigolds