You can also keep an eye on the Succulent City Youtube channel. Cactus cultivation is all about patience. However, it requires a steady hand and being attentive to any potential problems. When you plant your barrel cactus outdoor, things will change. For plants that are actively growing, you should apply a balanced fertilizer (e.g., 20-20-20) every other month. If the plant is indoors, it is better to allow it to enjoy enough sun. The plants will be more comfortable being outdoors once they have been used to indoor life.