Cultivating Carnivorous Plants (2015)
Basic Potting Mixes
If you are getting a plant that
is “bare root,” i.e. shipped
without any soil on its roots or
if you received a plant in slimy,
rotted soil, and you don’t know
what type of soil to use, default
to one part sphagnum peat
moss and one part sand or
perlite. But before you go out
and buy a bag of sphagnum peat
moss or sand, there are a couple
things to know. First, make sure
the bag of sphagnum peat moss
does not contain additives,
especially fertilizer. Although
carnivorous plants can be
fertilized, sphagnum peat that
already comes fertilized often
Some ingredients in carnivorous plant potting mixes include (clockwise
has fertilizer that is too strong
from top left): charcoal, coconut fiber, perlite, orchid bark, and long-fiber
for most carnivores and will kill
sphagnum. Sand and sphagnum peat are not photographed here.
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CULTIVATING CARNIVOROUS PLANTS
them. Second, when buying sand, make sure it is not beach sand. Salt will kill carnivores (and most other
plants, too). The best sand to use for most carnivorous plants is coarse-grained, silica sand.
The other default potting media is long-fiber sphagnum moss. This consists of long strands of dried out
sphagnum, a type of moss which can be found in many carnivorous plant habitats. Nepenthes, Heliamphora, and
highland tropical Drosera usually prefer long-fiber sphagnum moss over the basic carnivorous plant mixture. It
is airy and allows more oxygen to get through to their roots.
The thing to know about long-fiber sphagnum moss is that comes in a few different varieties, all of which
are named after their location of origination. The best quality is New Zealand or Chilean. This moss is thick,
almost plush, has few sticks and other debris, and is often sold under the title “orchid moss.” Long-fiber
sphagnum from temperate regions, such as Canada, Michigan, or Denmark, is often thin, full of debris, and
less expensive than the New Zealand moss. Don’t be fooled. The cheap stuff will degrade within a year and
be more likely to carry pests. In contrast, a good New Zealand moss should last around three years.
In the following chapters, I go more in-depth about potting mixes. The key thing to keep in mind when
buying ingredients is to make sure there are no additives or fillers. Also, be suspicious of claims of
“sustainable” mixes which use materials not often found in carnivorous plant cultivation. A few years ago, the
International Carnivorous Plant Society’s journal published an article about using (mostly) different kinds of
hydroponic clay for the cultivation of Nepenthes. I - and several others - tried the suggested mix and saw,
contrary to what the authors wrote, that after a few months, our plants were clearly suffering.