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.
Potting soil
Some plants require potting soil that is specific for their environment. For example, an African violet would grow better in potting soil containing extra peat moss, while a cactus requires sharp (i.e. plenty of) drainage, most commonly perlite or sand. But potting soil is not ideal for all contained gardening. Insectivorous plants, such as the Venus flytrap and the pitcher plant, prefer nutrient-poor soils common to bogs and fens, while water-based plants thrive in a heavier topsoil mix.