Carnivorous
Plant Growing Media
Most CPs require an acidic growing medium (hereinafter referred to as 'compost'), to match their wetland origins. An important plant in acidic wetlands is a moss called Sphagnum (Sphagnum is the name of the genus). When Sphagnum moss decomposes slightly, it is called Sphagnum peat moss, or more simply, peat moss. Use this for your first attempts at growing CPs. Peat moss is available in various quantities, and in the experience of most growers it is best to buy it in bales (300 litres). It costs about AU$43. This is a lot of moss, but if you become tired of CPs you can always use it in your garden. The reason to buy bales is that smaller volumes are often pre-wetted (so you are paying for water) or, worse yet, treated with chemicals such as wetting agents. These compounds seem to be toxic to some CPs. When you use peat moss, grab a hunk (it is usually compressed), crumble it to powder in your hands, and then add water. It is hard to wet. The best way is to submerge a handful, squeeze out the air, then slowly let it expand. It will draw in water. Do not use peat dry - it will never hydrate.
Most CP species grow well in a peat moss compost. In this part of the world a percentage coarse sand is favoured in varying amounts, depending on particular plants.
All the Sarracenia species grow well in a 4:1 mixture of peat and coarse sand.
Dionaea plants prefer the slightly better drainage of a 2:1 mixture; as do the various Drosera binata plants and many other non-Australian Drosera species.
Cephalotus and Brocchinia genera, together with the Australian pygmy Drosera and tuberous Drosera species, and some of the South African Drosera species - D. regia, and D. pauciflora in particular, should be grown in a 1:1 mix of peat and sand.
Byblis species prefer a drier compost consisting of 1:2 mixture of peat and coarse sand.
The terrestrial Utricularia species are much more water-loving. They prefer a 1:1 peat moss and sand compost, with a high water-table.
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Drosera stolonifera ssp. rupicola
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Some CPs prefer Sphagnum in the non-decomposed state. This is referred to as long-fibre Sphagnum. Some plants even prefer live Sphagnum. Finding long-fibre Sphagnum to buy may be difficult because few nurseries carry it. Do not buy 'green moss' or 'sheet moss'. This stuff is garbage, and is certainly not Sphagnum, despite what your well-meaning nurseryman may think. Nearly all nurseries think they have Sphagnum, but it is usually peat moss. Definitely avoid the material known as sedge-peat, which is sometimes available.
Moisten Sphagnum, if dry, as you would peat.
Warning: when manipulating dry Sphagnum, use a face-mask and gloves, as you may run the risk of contracting Sporotrichosis (see the 'technical topics' page for more details on this).
If you go to a Sphagnum bog, usually to be found in snowfall areas of many mountains, it is not appropriate to harvest big hunks of Sphagnum. If you must, take a few sprigs, but not bag-fulls.
Many of the tropical CPs grow well in pure live Sphagnum: these genera are; Nepenthes (both lowland and highland species), Heliamphora, Genlisea, Pinguicula, and the epiphytic Utricularia species. The Nepenthes plants benefit, in most cases, from the inclusion of about 30% orchid bark mixed with the Sphagnum.
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Drosera auriculara
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Many CPs like some additional drainage that is not provided by peat compost. A common additive in compost mixes is sand. Propagating sand or river sand, both fairly coarse-grained, are the best. It is available from many of the nurseries. Larger grain 'sharp' sand is also useful. Do NOT use ocean sand or bricklayer's sand because these contain too many salts. Certainly avoid bags of 'builder's mix' or other sandy compounds that are probably dry bags of concrete! Before using any sort of sand, it should be cleaned. Do this by filling a bucket halfway with sand, then run water over the sand while agitating the mix. The water is usually tan and opaque. But after a few such washings the water in the bucket clears and the sand is ready to use. The quantities of sand to mixed with other compost ingredients are itemised in those other sections. Warning: When using dry silica sand, use a respirator because you are risking Silicosis (see the 'technical topics' page for more details on this).
Some CPs prefer compost mixes including portions of vermiculite, perlite, live Sphagnum, orchid bark, or other additives. Feel free to experiment and by all means report your findings. Sadly, there are no solid, reliable recipes that seem to work for everyone.
