Three rules for carnivorous plants

Carnivorous plants break several rules you learned earlier, because they evolved in wet, nutrient-poor places such as bogs. They catch insects to make up for poor soil.

Rule one: mineral-free water. The United States Botanic Garden advises against tap water and mineral water; rainwater or distilled water is ideal. Minerals in tap water, especially calcium salts, build up and can kill these plants.

Rule two: no ordinary potting mix and no garden soil. Most are grown in live or dried long-fibre sphagnum moss, or a mix of about three parts peat to one part clean, sharp sand. Where insects are scarce, the Botanic Garden suggests a very dilute feed only while plants are actively growing, especially for tropical pitcher plants, and never feeding pieces of meat, which the plants cannot digest.

Rule three: lots of light. Most want bright light, and some, such as American pitcher plants (Sarracenia), do best in direct sun. A dim room is one of the commonest reasons they fail. They also like high humidity and, in the growing season, mix that stays moist to wet.