When to Sow Outside: 1 to 2 weeks after your average last frost date, & when soil temperature is 70o-80oF. When to Start Inside: RECOmmENDED. 4 to 6 weeks before your average last frost date. Days to Emerge: 5-14 Days Seed Depth: Seed Spacing: A group of 3 seeds every 9-12 Thinning: When 2 tall, thin to 1 every 9-12 Marigold Kilimanjaro White Heirloom Seed 30