Astrophytum myriostigma cv. Onzuka Cultivation and Propagation: It is relatively easy to grow. It is sometime seen as a grafted plant but grows very well on its own roots too. Water sparingly from March till October and keep perfectly dry in winter at temperatures from 5 to 15 degrees centigrade. (but it is hardy to -7°C for short periods). In the rest period no high atmospheric humidity!!
Sun Exposure: Light shade to full sun. Be careful: The epidermis of ONZUKA is harder than in the normal myriostigmas and cracks easily if plants are overwatered.
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz
