Mammillaria gracilis, is a small cactus with somewhat slender, cylindrical, bright green body clustering and branching freely, but the offsets easily detached. Mammillaria propagation is similar to that of almost any other plant. Usually seedling takes a quite long time to form plants, so many people consider pruning a great way of plant division. How to prune mammillaria? There are little offsets, clustering around the plant. They can be easily pulled away and placed in a dry and warm location to form calluses. As this is an indoor plant, it is essential to know how to grow it in pots. Cacti like being in little pots and require repotting every 3-5 years. In cultivation the temperature must be kept between 20 and 30 degree Celsius. It is allowed to fall to 15 degree at night, when it is summer time, and to 18 degree during winter months. One of the optimal ways of keeping the plant during the summer is growing it outside starting from May and through September. Simply place it in a sunny spot, as there it can get strong sunlight. Make sure it avoids the strongest midday sun. Starting from September and up to May cacti must be moved to cool west or east windowsills.