H. aulicum potting mix

Dennis Szeszko dszeszko@gmail.com
Fri, 11 Apr 2008 09:30:56 PDT

It is interesting that you mention using horse manure as part of a potting
mix.  However, I think that you need to mention that it needs to be
composted and cannot be added "fresh" because it may release too many
nutrients too quickly and burn plants.  I find horse manure a WONDERFUL
addition to all sorts of potting mixes....especially terrestrial orchid
mixes.  Although it seems counterintuitive, composted horse manure is
relatively inert and it does not engender growth of fungus or bacteria that
would be deleterious to the geophyte.  (At least not in my experience).
Also, it functions as a slow-release fertilizer to the plant.  I got the
idea to use horse manure a few years back when I read about an orchid grower
who used only 100% composted horse manure as a medium to grow Disa.  For
those of you who don't know, Disa is a genus of African orchids that are
very difficult (almost impossible) to grow ex-situ because they are very
sensitive to pH, dissolved salts and impurities in water.  I figured that if
fussy Disa orchids can be grown beautifully in horse manure then perhaps it
would be interesting to experiment with using horse manure with other
terrestrial orchids.  I use a mixture of 25% composted horse manure, 25%
mulched oak leaves and 50% sand to grow my terrestrial orchids and it gives
terrific results with Bletia, Funkiella, Dichromanthus, Schiedeella, and

Uli, you mention that the potting medium you use is "too fine for orchids",
but the potting mix you describe (without perlite or the amendment of
commercial growing mix) would work for some epiphytic orchids in the
Catasetinae tribe.  (e.g. Catasetum, Mormodes, and Clowesia).    This
potting mixture placed in an open basket would be excellent for potting a
vigorously growing Catasetum.  I use pure horse manure to grow my Catasetums
and it does the trick.

> Dear All,
> Sorry to be so late in answering to questions! I grow Hippeatrum aulicum
> in an open compost made of shredded wood composted with grass clippings
> and horse manure. This wonderful compost is mixed with perlite and
> commercial potting compost.It works wonders on epiphytic cacti and also
> on the two epiphytic Hippeastrum species, H.calyptratum the other. I saw
> them in nature growin on moss covered tree trunks where the large fleshy
> root system formed extensive thick structured along the trunk. This
> compost is too fine for orchids, except terrestial ones and
> unfortunately tends to decompose further.
> Greetings from cold and frosty Germany, Uli

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