Why is the bottom of my cactus turning brown?
Sometimes if water does not evaporate around the base of a cactus, the plant can develop a dry sort of rot. Some cacti also develop brown dry spots along their columns over the years. Be sure that the soil is truly dry when you do water. Also place stones and gritty sand grains and pebbles on soil to help dry out the top of the pot.
Your soil should be porous but also have a retentive quality. It must retain water so you don't have to constantly water the plant. A good soil allows excess water to drain off yet still retains enough moisture so that the plant doesn't become stressed between waterings.
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service