Cactus can do very well in containers if attention is paid to several things. One, use terracotta, it breathes well. Also, make sure there is a hole in the bottom because the soil shouldn't be sitting in water. And importantly use a Cactus soil mix, a mix that has a lot of sand, a lot of perlite. Although most plants don't thrive in mixes with a lot of sand, because it dries too fast, Cactus requires this condition. In fact, over watering is the number one way to kill a Cactus. To place the...