Q.Osteospermum
What type of soil is best to use when starting Osteospermum from seeds?
Certified GKH Gardening Expert
Any good standard potting mix will usually be sufficient. You may also choose a soilless potting mix. Here is more info: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soilless-growing-mediums.htm
I shall make the assumption that you're starting your seeds indoors. Use any good seed-starting mix. This article has more information about these lovely plants: https://www.gardeningknowhow.com/ornamental/flowers/african-daisy/african-daisies-osteospermum.htm