Tropical pitcher plants belong to the genus Nepenthes which contains about 120 different species all native to the old world tropics from Madagascar to Australia, with the highest concentration in southeast Asia. The elegant and sometimes colorful traps are modified leaves that catch insects to supplement the plant's nutrients. Nepenthes are increasingly finding their way into floral shops and gardening centers, but these can be tricky to grow because of their temperature and humidity requirements.
Tropical pitcher plants are broken up into two different categories--lowland and highland--based on where they originated. Lowland plants prefer temperatures in the range of 60 to 70 degrees F at night and 80 to 90 degrees F during the day. Highland plants prefer slightly cooler conditions associated with the higher altitudes in tropical regions. Highland species should be kept at 50 to 65 degrees F at night and 70 to 85 degrees F during the day. They can tolerate slightly higher and slightly lower temperatures than what is suggested, but do not do well if there are dramatic swings in temperatures.
Tropical pitcher plants are vines that grow their way toward the forest canopy in competition for light. They can tolerate low levels of light like what you would find near the jungle floor, or the bright dappled shade of the upper canopy. Plants grown in full sun often show some burning on the leaves and pitchers, but it may help with flowering.
Tropical pitcher plants are very adaptable to different types of soil. They can live in any soil mix that is loose and airy, free draining and not prone to rot but still retains moisture. A popular formula is half sphagnum moss and half perlite. Some growers also use fine-grade orchid bark or coconut husk fibers in the potting mix.
Tropical pitcher plants do not like to sit in water, unlike the North American pitcher plants. However, they do not like to dry out. Even medium-moist but not soppy soil is best. Humidity needs to be very high constantly, preferably in the 70 to 100 percent range for best trap development. Most of the time this can only be achieved in a greenhouse or terrarium.
There is a lot of debate among growers as to whether or not to fertilize tropical pitcher plants. They naturally obtain their own fertilizer by trapping and digesting insects. Fertilization seems to reduce the number of pitcher a plant produces. Many growers recommend keeping the plants "hungry" to stimulate them to produce more traps. Other growers recommend giving a diluted dose of balanced water soluble fertilizer once a month or just at the beginning of spring.