Jade plants can be interesting succulents. They have fleshy, woody stems, and are similar in size to small tree trunks. Put the cactus seeds in one or more small jars. They will grow well outdoors in the summer. This works well with the types of grit/grity mix we've already mentioned. You can use four different types of lights as grow lights. As long as the Fairy Castle Cactus's active growth is ongoing, you can add plant food to the soil or water to ensure it has the proper nutrients. You should water your plant approximately once every two to three weeks.