Succulent seeds, cactus seeds, Lithops seeds. We have them for you. Most seeds can be germinated in our Cactus and Succulent Soil Mix. Very small seeds from species like Lithops and Echeveria do not want to be covered with soil. Average seed germination temperatures are around 24C. Species like Adenium and Pachypodium like temperatures around 28C to germinate. Lithops usually germinates best at temperatures around 20C.