Cactus
There are over 2,000 varieties of cactus. They are native throughout the Americas and Africa mostly from regions that experience drought. Cactus come in all sizes, shapes and colors. Almost all cactus are also succulents. They are characterized by enlarged stems used to store water. Most have no leaves but spines which are highly modified leaves. They have evolved as a defense mechanism for the plant and also help to prevent water loss through providing shade and reducing air flow. Cactus stems are generally ribbed or fluted to enable it to expand and contract based on water gain or loss. The following instructions are for general cactus care. Some varieties may need slightly different care so always look up the specific variety as well.
Light: Bright indirect to direct light; south or west window.
Watering: Always allow soil to dry out completely before watering. Water slowly and evenly until water comes out of the drainage hole; discard excess to avoid root rot. Generally water once per month in the winter and once per week in the summer.
Humidity: Dry to average home humidity.
Toxicity: Many cactus are non-toxic however some varieties are so look up your specific variety to know for sure.
Potting Mix: Fast draining, well aerated and dries out quickly after watering.
Additional Care: Overwatering is the biggest cause of cactus death. Depending on the cactus size, use tongs, gloves, newspaper or blankets to move/repot.