Ted Byers wrote:
"Ray" wrote in message
...

Ted,

Even though they were once lumped into a single genus, tolumnia and
oncidiums are quite different in their natural cultural conditions.


Out of curiosity, how similar are they morphologically? I did a search for
pictures of Tolumnia using google, but the links I have pursued so far have
only shown images of the flowers, which look much like the flowers of the
Oncidiums I have seen.


If I recall correctly (I may be overgeneralizing, but you'll get the point
anyway), tolumnias typically populate spindly branches of shrubs on the
windward side of Caribbean islands and nearby mainland locales. As such,
they are bathed in constant breezes and dry out almost instantly after
rains. Many oncidiums, on the other hand, and more typically
"jungle-based," with the overall wetter conditions seen there.


Do they have the adaptations one would usually expect in plants living in a
relatively arid environment, such as fleshy leaves, perhaps proportionately
larger pseudobulbs than the Oncidiums, roots that are better designed
against dessication than one would expect from a rainforest epiphyte?

I have never actually seen a Tolumnia in the flesh.


Every attempt I have made to grow tolumnias in true S/H conditions has
failed, which I rationalize by thinking about the vast dissimilarity of
that root climate to that of the twigs. On the other hand, every
pseudobulbed oncidium I've tried - Sharry Baby, a couple of species, and
any big yellow "dancing doll" included - has thrived.


Given what you have said about their natural environment, I would be
astonished if they were found by someone to thrive in semihydro. If there
are people who succeed in growing them in semihydro, what is the reason?
Are they doing it in an environment that has much drier air, and thus much
greater evaporative demand? If so, I could see that demand drying the air
in the pores within the media, while the water in the pellets supplies
sufficient water for the plant to meet that demand. If that is right, I
could see the plant growing faster than normal since plant production is
often correlated with evapotranspiration rates (at least in crop plants I've
studied - I don't know how well that empirical relationship applies to
orchids, if at all).


My statement that I have the ascocentrums in clay pots of PrimeAgra was
meant to point out that PrimeAgra can be used as a non-S/H growing medium.
I did not say they were in S/H. But let me throw some more confusion into
the fray: I would not recommend ascofinetia be grown in S/H, even though
some folks are good at it, but I am successfully growing Neofinetia
falcata that way.


OK, I misunderstood you there.

If Neofinetia does well in semihydro, but Ascofinetia does not, should that
be taken to mean that Ascocentrum does not particularly like semihydro, and
has passed that trait on to Ascofinetia? If not, what is the reason you
wouldn't recommend semihydro for Acsofinetia even though some succeed with
it?

And here is a question about semihydro that is completely unrelated to
orchids, unless there are orchids used as herbs in some cuisine with which I
am completely unfamiliar. My neice is training to be a chef, and I thus
tried to get her started in growing her own herbs, but to no avail. She
must have thumbs even blacker than her mother and aunts, who can even kill
plastic plants. ;-) The question is, if we have some seeds for a number
of herbs, how can we get them germiinated and then growing in semihydro. My
hope is that if we can get them growing in semihydro, she will be able to
maintain them by simply restoring the initial water level in the reservoir
when that drops by a centimetre or two. She is one that often forgets to
water her plants, and so they usually die from dessication! Of course,
seedlings are much more vulnerable to her than a relatively mature plant,
but even they die from dessication eventually. I'd like to try to make
taking care of plants as easy as possible, to improve her chances of keeping
the herbs healthy enough to use in her outstanding cooking. It is amazing
to me that such an outstanding chef could be so severely challenged when it
comes to keeping plants healthy!

Cheers,

Ted


Now that would be a fun thing to try... put a few herbs in s/h and see
what happens... I wonder about the hard woody varieties vs the soft
plants (like thyme vs basil for example) Come to think of it, I think
most herbs get a better taste from hard rocky growing conditions... but
that may be just another myth.
I'll bet if you started growing seedlings standing in water then
transferred them to s/h you'd get a better survival rate... in order to
allow for morphologic root changes between the culture methods.

K Barrett