Cultivating Carnivorous Plants (2015)
The last “basics” which will not be covered elsewhere is fertilizer. Older carnivorous plant manuals and
some growing guides that have not stayed up with the times will say “never fertilize carnivorous plants.” This
is the biggest fallacy when it comes to carnivorous plants. Most plants can be fertilized, it just requires a
The most realistic fertilizer is insects. For plants outside, they will catch plenty of their own insects. For
plants inside, you might have to supplement with freeze-dried bloodworms, dried crickets, etc. These “food”
items can be found in most pet stores worldwide, as they are often used as food for pet reptiles or
amphibians. Freeze dried bloodworms, or other small insects, work well as food for Byblis, Drosera, and other
sticky-leaved carnivores, which often do
not respond well to foliar fertilizer. For
plants that are adapted to catching
smaller insects, such as Pinguicula or
pygmy Drosera, you’ll want to powderize
Otherwise, you risk burning the leaves as
the bloodworms are incredibly rich in
For larger trapped plants, such as
Nepenthes and Sarracenia, it would quickly
become expensive to buy enough insects
to feed the plants. It is usually much
fertilizer pellets aimed at flowering plants
(~14-14-14 NPK) and place one or two
pellets in each trap. Since these pellets
contain a hefty dose of fertilizer, small
traps should only get a small pellet in
order to avoid leaf burn. Larger traps can
handle a few pellets, but note that if they
congregate at the bottom of the trap,
they can cause leaf burn.
Recent experiments by some growers
have shown that adding a few of these
pellets into Nepenthes or Sarracenia mixes
(usually two or three per medium-sized
pot) can boost growth. Usually, however,
Some commonly used fertilizers include:
I simply place them in the plant’s
MaxSea, Osmocote, and Bloodworms.
trapping apparatus, which is already
designed to absorb nutrients.
Many carnivorous plants also respond well to foliar feeding with orchid fertilizers or seaweed based foliar
fertilizers diluted to ¼ - ½ their ordinary strength. The brand most often mentioned in this regard is MaxSea
(16-16-16- NPK), but other brands work equally well. I would recommend first using a foliar fertilizer on a
test plant or two before applying to a whole collection. That way, you’ll avoid burning more than one plant, if
the fertilizer turns out to be too harsh for carnivores.
CULTIVATING CARNIVOROUS PLANTS
Please note that some genera, such as Pinguicula and Drosera, often do not respond well to foliar fertilizer.
Others, such as terrestrial Utricularia, can really only be fertilized effectively by using foliar fertilizer.
Many growers are beginning to experiment with introducing mycorrhizal and trichoderma fungi. This is a new
area of fertilization, and much is still unknown with regard to carnivorous plants. Both of these genera of
fungi have symbiotic relationships with many plants. This symbiotic relationship allows the plants to uptake
soil nutrients more effectively and, in exchange, the fungi get some other nutrients back from the plants. So
far, these two genera of fungi seem to boost the growth of most species of Nepenthes, but experiments are still
ongoing for other genera.
Lastly, I have to mention coffee. Brewed, cold, leftover coffee without any additives is a good basic
fertilizer for Nepenthes. Since coffee beans are naturally designed to be high in nutrients, as they are the
foodstuff for newly germinated coffee plants, it should not be surprising that brewed coffee is high in
nutrients good for plant growth. Innumerable growers have experimented with dumping leftover coffee on
their Nepenthes and found that it does, indeed, promote growth. Note, however, that it does have a couple
drawbacks. First, coffee can kill live sphagnum moss. Many growers plant their Nepenthes in live sphagnum
and coffee fertilization does significant harm to the sphagnum, which can be avoided by feeding with orchid
fertilizer. Second, using coffee will result in a persistent, if faint, smell of coffee near your collection. Not
everyone may be pleased to smell coffee all the time.