Simple Rules for Successfully Growing Carnivorous Plants
Maintaining constant moisture
Carnivorous plants can be found in the wild, growing in bogs and other conditions which are poor in nutrients. As a result, these plants exist in growing conditions which are perpetually wet. So it follows that in order to grow strong carnivorous plants the grower needs to emulate their natural environment as closely as they can; which includes keeping the growing medium damp at the very least or wet.
The most practical manner in which to accomplish this is to use a tray below the container of the potted plant. Maintain a level of 2-4cm water in the tray at all times. When the water level drop be sure to add water to the tray rather than directly to the plant, from overhead. This is particularly not advisable for Sundews as this will wash away the sticky muscilage found on the leaves. It may also result in the leaves of flytraps closing unnecessarily.
Water free of minerals
You should try to avoid using tap water for your carnivorous plants, and if you do need to in an emergency then try not to for an extended period of time. The problem with tap water is that it contains many minerals and salts which are not good for the health of your carnivorous plants as they may fertilize or even burn your plants. When you are again able to find the prefered water type then its advisable to flush the plants with this to remove any accumulation of salts and minerals.
The best water to use will be rainwater, followed by distilled or RO (Reverse osmosis) water. You can collect rainwater from the downpipes of your house when it rains, and you can even collect the water which forms in the condensate line from air conditioners and heat pump other source of mineral-free water.
Soil free of minerals
In their natural habitat, as has previously been mentioned, these plants grow in conditions which are very nutrient poor. It stands to reason then that when trying to emulate or duplicate these conditions the soils your provide to your plants needs to conform to the same basic requirements. As the raw materials used in suitable growing media is usually only available in sizeable quantities it is recommended that the average grower simply purchase the required amount of ready-mixed soil rather than mixing their own.
It's recommended that you use plastic pots to grow your plants in and clay containers will leach minerals after some time and this may in turn again place your plants under some stress.
Plenty of light
Sunny conditions, generally, are where all carnivorous plants will grow best although some will do well in partial sun. Due to the nutrient-poor growing conditions these plants grow in, plants tend to be stunted in height and thus these areas are usually found to be open and exposed to the sun.
For most carnivorous plants, when they are placed in full sun, their full colours will be displayed, especially reds. Despite this many carnivorous plants will grow rather well indoors as well so long as they are placed in a bright, sunny position. If you wish to improve their growth indoors you can provide further artificial light for around 12-14 hours a day. Conventional light bulbs will not be as effective as purpose designed fluorescent tubes which provide the ideal spectrum of light to stimulate plant growth.
Allow the plants to go dormant
Many carnivorous plants require a period in which they go dormant. This is entirely natural and is actually a protective mechanism which ensures the plant will survive the winter in its natural habitat.
Drosera and Nepenthes will not go dormant and will continue to grow slowly during winter although it is advisable not to allow Nepenthes to get too cold. Sarracenia and Venus Flytrap do go dormant and should not be fed during this time and should simply be kept moist but not wet. If these plants are not allowed to rest, for instance by keeping them too warm, they will deplete their energy and may eventually die. So when you see plants begin to show signs of dormancy reduce the amount of water given to them so they are only slightly damp. You can then also keep them in a cool, shaded area for between 3 and 6 months. Carnivorous plants don't need light when they are dormant so even complete darkness will not harm them although just don't forget to move them again when they begin emerging from dormancy!
Levels of humidity
The natural habitat for carnivorous plants will be humid. Usually keeping the plants in a tray with water will accomplish a very similar environment. If you're growing your plants indoors and really want to create the ideal spot for them then a humidifier placed near the plants would be ideal. Some growers choose to grow their plants in an open terrarium, which will of course be much easier and arguably prettier than a humidifier.
The average room temperature will be fine for most carnivorous plants and these plants are usually quite forgiving of temperature fluctuations and ranges.
Fertilizing your plants
Broadly speaking, you should not fertilize carnivorous plants. Plants are usually able to catch sufficient insects to maintain health. In fact most plants need very few insects to grow well, 1 or 2 a month is sufficient. If you do choose to feed your plants, never feed raw meat or cheese to them. However, try to grow the plants in a manner that they will have a chance of being exposed to insects though.