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  potting mix
From: Ken Mosher ken at spatulacity.com> on 2005.12.17 at 18:27:33(13610)
MJ and Hermine,

I will post my results, but it will take at least one year, if
successful, or more if I have to try again. In the meantime we can all
benefit from the advice that's flowing back to us now.

MJ, our problem is a very bad one because of the high rot danger. It
must be cured!

From: plantguy at zoominternet.net> on 2005.12.18 at 06:05:13(13613)
Hi Ken,

Well, as you know I use only pine bark and perlite anymore. It is
interesting about the pine bark comment earlier. You can surely tell where
people live almost by how they talk about pine bark. Here in the north it
is a non-starter to get any little fungi growing on top of your potting mix
containing pine bark unless something is really wrong, but I know that the
Frittilaria growers out in Oregon (Jane McGary) despise it because it causes
their Frits to rot! The Frit growers in Philadelphia (John Lonsdale
Edgewood Gardens) at have no problem at all wth pine bark. I imagine the
humidity down south causes the same problems.

I have also found that any peat based product is a guarantee for rot in my
climate. We are simply too cool in the summer with too much rain here in
Pittsburgh. I've read that we get the second highest rainfall for any major
metropolitan area in the U.S. and I can believe it!! I should say that I do
not have a greenhouse so that very much limits my possibilities in terms of
restricting water. I could not agree more with Derek's comments about
watering as anyone that grows bonsai knows the Japanese take watering of
these plants very seriously. Unfortunately, for those of us who grow our
collections outside in the elements it is usually not me that does the
watering but good ol' mom aka mother nature :o)

I have tried a different mix for my titanum, hewitii, decus-silvae, gigas
and a few others recently that stay inside all year (Dracontium also). I
use turface (this is high fired clay and so is very, very porous but holds
water in the pores much like the high fired clay pellets that you use for
hydroponic growing) mixed with the pine bark and charcoal (roughly 2:2:1).
While I have only used this for approximately 2 years it seems to work well
and I have not lost any to rot as of yet (knock on wood). I tried this
because it is what I use for my bonsai collection for the past 15 years and
the people at Phipps conservatory use it for their titanum and bonsai as
well. You can buy turface by the pallet full also, but my needs are no
where near that great!!

I think it is very important when considering a potting mix to look at where
you grow and your climate and or greenhouse conditions. I just do not think
that what someone uses in Miami or Tuscon will work for me here in
Pittsburgh without some modification. Our climates are soooooo different
that it is hard to extrapolate from one to the other. Of course, if they
use a GH where the only water is from a well-monitored hose then all bets
are off. There is nothing quite like 25 out of 30 days with rain and highs
in the high 70s to low 80s (F) (the summers of 2003 and 2004) to make you
appreciate drainage and rot in a whole new way!!!

Unfortunately, I really think that like most things in life it is
trial-and-error coupled with listening hard and long to your mentors (I've
e-mailed many of you with questions like this) until you think that you have
it right and then your favorite plant gets kicked over by the kids anyway

From: "Russ" chammer at cfl.rr.com> on 2005.12.18 at 10:30:28(13615)
Dan in Gibsonia,

Interesting about your pine bark and perlite mix. What size pine bark are
you using? Finely ground or something larger? Here in central Fla, I have
finely ground bark available, and the wood chips for landscaping,
but no in-between size that I know of. What ratio of bark to perlite?


From: plantguy at zoominternet.net> on 2005.12.18 at 18:38:33(13621)
Hi Russ,

I would estimate that the pine bark is perhaps 1/4 to 1/2 (very large) inch
in size.....more or less. In Alabama when I used to grow a lot of
bonsai....now I only have around 10 of my favorites that I bothered to keep,
we would have sifting and mixing parties to get rid of the small bits.
Basically you had screen conveyor belts that you put the pine bark on and
they vibrated to get all the small bits out. This brings up one more point
that I do not think was touched on. Remember, drainage is determined by the
smallest size particle in the mix....you can put all the big junk in you
want and the small ones determine the total water holding capacity of the
mix. This is why in bonsai, where drainage is critical, all good
growers.....not potters as Dewey says, but "growers" sift their potting mix
to get uniform sizes. If you really want to learn a lot about the physics
of water movement through "soil" then the bonsai forums are your place to
get an earful :o) I use a 50:50 mix and by the end of the summer when I
take the tubers out the pine bark has nearly disintegrated and so does not
drain as well....the particles are smaller so drainage has decreased....it
is true what they say....size matters.

As I said though, and as Dewey reiterated....he has knowledge about FLA and
I have knowledge about PA.....I would listen to his advice, as I have in the
past, but then eliminate what I know is useless info based on my own
personal experience and try to incorporate the new knowledge as best I can
in my never ending trial-and-error plant life. However, Dewey, if you are
not willing to toss in your two cents then who?? We can all learn a great
deal from the collective wisdom of growers such as yourself, Tony, Wilbert,
Alan, Derek, etc. etc., but only if you offer a couple of cents every now
and again.

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