Grow lights are essential for succulent and cactus growth in those who don't have a greenhouse or bright, sunny windows. Cacti require direct sunlight, but if your cactus will be kept indoors, you will need to expose it to 12 to 14 hours of full-spectrum light. If the symptoms are not visible on the plants that are above ground, then you will need to use them. Finally, the South African hedgehog monkey tail Cactus is also native. You can remove the slimy, black roots and leave only the healthy ones.