Question
Hi,

I have purchased some plants from you,and they are all doing very well.  My question is have you considered adding charcoal to Flytrap/Sarracenia soils?  I understand that they do controlled burnings in the Green swamp and other places where these plants grow in the wild (I recently visited them there, and they were awesome!).  I got this idea when I recently changed my Nepenthes soil,and added Charcoal into thier soil, and they seem to have really loved it....So...Anyone ever try charcoal with the other Carnivores?  Thanks!

Answer
Hi Dan,

I've included an article that I wrote for our newsletter last summer.  After reading it, you can decide if charcoal should be an essential part of the soil mix.

With field burning, the main thing that carnivorous plants (Sarracenia and flytraps) benefit from is the removal of other vegetation that blocks sunlight.  These plants flourish in full sun, so if there are grass and shrubs that block the sun, field burning will remove these plants and allow pitcher plants and flytraps to flourish.  (Sarracenia have large rhizomes, which are protected in the soil during field burns.)  So it's not so much the actual ash in the soil as much as it is sunlight.

Your Nepenthes most likely improved in growth by the extra aeration that charcoal provides.  You can also improve aeration a bit more cheaply by using chunks of pumice.

Good growing!
Jacob Farin



DOES CHARCOAL REALLY PURIFY THE SOIL?

Have you ever unpotted a plant and got a huge whiff of a foul
smelling odor?  That is the sign of soil gone bad.  When this
happens, your plant will definitely need a dose of fresh soil.

What cause soil to go bad are the eventual breakdown of peat
moss and the growth of bacteria.  Bad soil will often smell like
rotten eggs or dirty socks.

Some gardeners recommend adding horticultural charcoal to
reduce the foul smell and to keep the soil fresh.  The idea is that
charcoal will absorb the foul smell and improve soil quality.  They
recommend using a soil mix that has about 10-20% charcoal.

But does charcoal really purify the soil and reduce the foul smell
of soil gone bad?

We used charcoal in the past, but we could not tell any
noticeable difference in plant growth or in soil quality after a
year or so.  When you really think about it, adding charcoal
would only improve drainage, nothing else.

In order for charcoal to absorb the compounds responsible for
the foul smell of soil gone bad, it needs to be activated or
super-heated.  This causes the charcoal expand like popcorn
and improves the filtering of organic compounds.

Carbon-based water filters use activated charcoal.  Horticultural
charcoal is not activated, so it lacks the ability to really absorb
anything.

Secondly, charcoal has a finite volume.  Adding charcoal to
make up 10-20% of the soil volume is not going to have any
odor-absorbing properties after a few minutes sitting in the soil.  
It is like placing a small sponge into a sink full of water to absorb
all of the water.  

With this in mind, adding charcoal to a soil mix will not have any
long-term benefits.  After a very short time period, it is still
possible to end up with foul-smelling soil, even with the addition
of charcoal.

So if you are thinking about adding horticultural charcoal to your
soil, you might be better off changing your soil on a yearly basis
for clean, fresh soil.    If you decide to add charcoal, any
improvements in soil quality might come from the increase
drainage.  If that is the case, it would be much more
cost-effective to use pumice, orchid bark or an extra scoop of
perlite instead.