Gymnocalycium horstii is a globular cactus resembling a loaf of bread from a bakery. Plants have a squat appearance and spines that are curved back towards the body. Plants usually offset over time, creating interesting specimens. The body of this species is glossy and the flower is always white.
Gymnocalycium horstii is a very rare and threatened South American species and occurs only in the southern Brazilian province of Rio Grande do Sul.
From the months of March to September when this cactus grows, fertilize once a month. When fertilizing, dilute the fertilizer to about a quarter to half strength.
This cactus will do well in a general cactus mix consisting of components such as coarse sand, perlite, pumice, or vermiculite. Gymnocalycium horstii is slightly frost resistant and grows best in semi-arid conditions. They typically grow on agricultural terrain that is made for things, such as cattle-grazing.
You can prune the flowers when they start to wilt. If you find this step necessary in the care of your cactus, it may be best to prune while the plant is growing during the months of March to September.
TEMPERATURE. In its native environment, Gymnocalycium horstii grows in temperate lowlands and grasslands. This means it grows in semi-arid and not too hot nor too cold conditions. As a result, they can withstand temperatures from 30 degrees Fahrenheit (-1.1 degrees Celsius) to 50 degrees Fahrenheit (10 degrees Celsius)