In this study an extract of Aschophyllum nodosum was used to improve growth and flowering in plants of Rebutia heliosa and Sulcorebutia canigueralli. The two experimental groups in cultivation were: i) group without the use of Ascophyllum nodosum (CTRL), irrigated with water and fertilized every two weeks; ii) group treated with 10% Ascophyllum nodosum (AS) powder mixed with the substrate, irrigated with water and fertilized every two weeks. All plants treated with Ascophyllum nodosum showed a significant increase in the agronomic characteristics analysed. The cacti (Rebutia heliosa and Sulcorebutia canigueralli) grown in the algae treated substrate showed a significant increase in plant height, suckers number, vegetative and roots weight, plant circumference, flowers number and flower time and seed germination. Effects certainly due to an improvement in the nutritional status of the plants induced by an increase in nutrient assimilation, which manifests itself in increased stress tolerance. Positive effects can be found especially on plant species that have difficulty in germinating, rooting and flowering or as in this experiment on plants that are slow to grow or have difficulty in being grown in greenhouses and in climatic conditions different from those in which they originated.