The Best Time to Plant Vinca Annuals

Starting Seeds

• Start vinca seeds indoors 10 to 12 weeks before the last estimated frost of the spring season. The seeds germinate best when a room temperature of 77 degrees Fahrenheit is maintained, according to the Colorado State University.

Seedling Planting Time

• Plant the vinca seedlings outside when all danger of frost has passed. The temperature needs to stay above 65 degrees Fahrenheit before planting the seedlings outside. Once established the plants produce blossoms in shades of red, pink and white from late spring until the first fall frost.

Planting Requirements

• Vinca plants are usually available throughout the spring months and into the early summer. The plants easily transplant after purchase. Plant in full sunlight. The vinca thrives in slightly acidic soil temperatures with a pH of 6 to 6.5.