Sow Vinca seed indoors 10-12 weeks before your last frost. Starting your seeds later is fine. Use individual cells or flats. Press into soil and lightly cover. Vinca seeds need darkness to germinate. Cover flat with newspaper or place inside black plastic trash bag. Keep out of direct sun. Kept at 75-80F., germination is in 10-21 days. Remove newspaper cover or trash bag and provide direct light as soon as the first seeds begin to sprout. When plants have 3-4 true leaves transplant into 2-3 in. containers. Place Vinca seedlings into the garden 12 in. apart when soil and air temperatures are consistently above 65F.