The Stenocereus pruinosus succulent is also known as the Gray Ghost Organ Pipe. Well, the most common sign is discoloration caused by over or under-watering. A: You can touch your succulent plants, but only if you wish to check for discoloration or signs of pests and diseases. The following are indicators that your succulent may be outgrowing its container. Some aficionados prefer to place a saucer of water under the pot and allow the cacti roots to pull the water up. If it is completely dry when removed, it is safe to water. Do not place it in direct sunlight.