Cleistocactus strausii
Silver Torch cactus can thrive in low-nitrogen soil without facing the consequences of low nitrogen. Too much water will make the plant weak and lead to root rot. 
Least Concern. This cactus is locally abundant in its native land and has few local threats to its survival.
This cactus can be propagated by cuttings or seed.
Parodia leninghausii
As most of the cactus, they need well drained soil, sunny exposure, regularly watering in summer and not at all in winter. In temperate climate, keep them outside in summer. In the wild and in winter, plant accepts frost at -4 °C if totally dry. In cultivation, it is preferable to keep cold temperature, but more than +2 °C.