Carnivorous
Plant Environment Essentials
Pure water is essential, as that is what the CPs expect from their wetland backgrounds. The tap-water or well-water in many areas contain too many chemicals, including calcium. Over time, these chemicals will kill your CPs. In Melbourne area the normal tap water is sufficiently pure for CP usage. Otherwise most growers use either rain, distilled, or reverse osmosis water. Good-quality reverse osmosis (RO) units work very nicely. Water softeners are not helpful since they add as many chemicals as they remove. If you are starting, stick with rain water (or tap water, in Melbourne) so if you have trouble, you know the water is not to blame.
How wet should the compost be? Remember these are mainly wetland plants. They want water. If you squeeze a handful of the compost, expect water to run out through your fingers and track down your arm. Wet wet wet. A few require a dry season, like tuberous Drosera in the summer months; but most want it wet. Keeping your pots sitting in a tray of water is a good idea for many CPs - but not for Nepenthes, Heliamphora, Byblis, Drosophyllum, and Pinguicula plants, and Cephalotus in winter months.
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Drosera stolonifera
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CPs, other than Pinguicula and Utricularia, require fairly high levels of light - most need full sun. Providing this for them is challenging. If you do not have a greenhouse or suitable growing area, you will need a brightly illuminated terrarium. For illuminating terraria, you should have at least four fluorescent bulbs approximately 30 cm (12") from the plants. Unfortunately, expensive grow-lights seem to do no better than inexpensive cool white fluorescent tubes. Some growers prefer the wide-spectrum or grow-lights (but do their plants?). Do NOT use incandescent light bulbs because they produce too much heat. Low pressure sodium vapour and mercury vapour lights are not useful.
Most CPs require high humidity conditions. A terrarium provides the 50 - 90% humidity most CPs desire. But since most plants desire some air circulation, do not seal the terrarium. Air circulation seems to be particularly important for the USA Pinguicula species, while Nepenthes do well in sealed terraria.
Some CPs grow in regions where the temperatures do not have much seasonal variation. These plants can be grown all year. But most grow in habitats that are inhospitable during some season. To survive these times, plants either produce seed and die, or become dormant. If you attempt to grow a plant that anticipates a resting period, you must respect its dormancy requirements, or else the plant will simultaneously try to grow and rest, and in the resulting confusion your plant will die.
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Drosera tubaestylus
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Different plants enter dormancy during different seasons. Many CPs rest during the cold of winter by forming tightly bound hibernacula or turions - some Drosera, Pinguicula, and Utricularia, are notable for this. Others, such as Sarracenia, Darlingtonia, or Dionaea, simply stop growing or die back to a rhizome.
Cold is not the only enemy. Excessive heat is another reason plants may hibernate. The tuberous and pygmy Drosera species of Australia are famous for their dormancy techniques. Tuberous Drosera plants regress to an underground corm for several months of the year. Simultaneously, the delicate pygmy sundews stop growing and try to survive the heat and desiccating winds by hiding within the shade of their dead leaves and stipules from the previous season's growth.
Some plants may not expect a significant temperature variation, but enter dormancy because of an approaching dry season.
It doesn't matter if you intend to provide your plant with luxurious conditions year-round. If your plant wants to enter dormancy you must provide an appropriately cold or hot resting period. Some growers don't like this because they want to enjoy their plants every day of the year. So they try to devise ways of keeping their plants awake past their bedtime! The only truly successful method is to grow some plants that are active during the winter, and some that are active during the summer - and this, of course, is a great way to feed the mania of collecting plants.
The high humidity and bright light requirements of CPs point many growers toward terrarium culture. This is fine, as long as you do not exceed the temperature extremes most CPs tolerate. Beginners may have good results growing tropical CPs. These plants do not enjoy temperatures much higher than 100°F (38°C). The challenge is to give your plants as much light as they want without cooking them. A useful solution is to cover a terrarium nearly completely with a sheet of glass, and then support the fluorescent bulbs a few cm above the glass. If you are handy, a small computer fan can be bought from electronic stores for a few dollars and easily modified to blow across the ballasts of the lights. Terraria illuminated by direct sunlight get very hot very quickly, and if not ventilated, will fry your plants. Tropical CPs are not frost hardy.
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Heliamphora heterodoxa
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Fertiliser and hamburger meat
As a good rule, never fertilise. Most fertilisers will kill CPs. Only a few types, such as Nepenthes, Ibicella and Proboscidea, seem to like particular fertilisers. But if you wish to capture a few insects and ghoulishly feed these live insects to your plants, enjoy! Dead insects are rarely accepted by the plants that use movement as all or part of their trapping mechanism - eg. Dionaea, Drosera. Certainly do not feed your plants pesticide-killed insects. Oh, and as for feeding Venus Fly Traps hamburger meat; that is a fine way to kill them. Venus Fly Traps are expecting insect prey, not small fragments of cows. If you don't think there is much difference, consider the following: would you like to eat a 'hamburger' filled with the bodies of dying insects?
Nepenthes plants grow well on a water-soluble fertiliser called Epiphytes Delight - this is available at the VCPS. Also Nitrosol, at half strength, has been found very beneficial for the same plants.