Rebutia teresae is a close relative of Rebutia heliosa, but a much easier plant to grow. It is both grows quicker and less pron to fungus rot.
This nice group of about 10 seedlings is two ears old from seed and already flowering.
The substance in the pots is my growing media. It is made of ceramic chips that are sold as soil conditioner for sport fields and called Turface (R). It serves as a perfect grow media for almost any cactus. All the nutrition my plants are getting with their water, as a weak solution of a regular low-nitrogen fertilizer with a full set of trace elements. This kind of culture with solid media for roots or without it is technically speaking called hydroponics, even if a lot of time the roots of my plants are properly dry.