Cotyledon hails from arid but not very hot regions, which corresponds well to the dry air of city apartments. All species of this succulent should be watered after the soil substrate dries out completely. During a cool dormant period (10-12 °C (50-54 °F)), watering is stopped. If the temperature remains the same during the dormant period, watering is carried out as usual. If the temperature rises to 28-30 °C (82-86 °F), watering can be done more frequently. Constantly moist soil and low temperature can lead to rotting and death of the plant. Water for irrigation should be taken at room temperature, settled or filtered. Dry air is required, just as in natural conditions. Only on the hottest days can it be lightly misted with lukewarm water, ensuring that water does not accumulate in leaf rosettes. If the humidity indoors is elevated for any reason, it is better to move the succulents into the fresh air.
It prefers bright lighting and a long daylight hours. During hours of active sun (midday hours), the plant must be shaded to avoid burns. It is best to place plants on south and east windows. With a lack of light, Cotyledon sheds leaves, stretches out, pales in color, and stops blooming. The most optimal temperature range in the summer period is 20-25 °C (68-77 °F). At this time, you can take your plants out into the fresh air: an open balcony, terrace, or veranda of a country house. During the dormant period (in winter), 10-12 °C (50-54 °F) is quite a comfortable temperature for the plant to rest and prepare for prolonged blooming. During this period, it is best not to water the succulents; only if the leaves have severely lost their turgor, the substrate can be moistened slightly.
In nature, these succulent species grow on poor soils. Therefore, at home one must also prepare a soil substrate similar to natural soil. It is composed of: 1 part clay-turf soil, 1 part leaf mold, 1 part washed coarse river sand, a little zeolite, a little crushed charcoal, bone meal, and fine-fraction expanded clay. Thoroughly mix all components to obtain an airy, loose mixture. The soil must be heated in an oven, and the river sand and expanded clay are washed in a weak potassium permanganate solution for disinfection. Such a mix is suitable both for repotting plants and for propagation by cuttings. If it is not possible to prepare the substrate yourself, you can purchase a ready-made soil mix for cacti in a specialized flower shop.
The plant has a fibrous root system, so plants are repotted using the transfer method. Do not forget to replace the old drainage with a new one. This should be done in spring. The signal that repotting is necessary is the foliage covering the entire area of the container. Mature plants are repotted into pots 2-3 cm (0.8-1.2 in) larger in diameter once every three years. The succulent grows slowly, so young plants should not be repotted - this inflicts unnecessary injury.
Fertilizers are applied only during the active period. During the dormant period, no fertilizers are added. Fertilizing begins once a month before the start of the flowering period. Fertilizer is applied after watering. Zeolite absorbs minerals along with water, then gradually releases them. Since in nature succulents grow on poor lands, overfeeding plants leads to excessive vegetative growth, and they may shed leaves or produce sparse blooming.
The most dangerous pest for Cotyledon is mealybug. It must be combated with a standard fungicidal agent. The succulent is not afraid of diseases, other than errors in plant care. In cases of overwatering and lack of light and fresh air, rotting of individual plant parts may develop.