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.
Cactus
Cacti are often grown in greenhouses, particularly in regions unsuited to the cultivation of cacti outdoors, such the northern parts of Europe and North America. Here, they may be kept in pots or grown in the ground. Cacti are also grown as houseplants, many being tolerant of the often dry atmosphere. Cacti in pots may be placed outside in the summer to ornament gardens or patios, and then kept under cover during the winter. Less drought-resistant epiphytes, such as epiphyllum hybrids, "Schlumbergera" (the Thanksgiving or Christmas cactus) and "Hatiora" (the Easter cactus), are widely cultivated as houseplants.