Green Culture Singapore Articles
& Photos: orchideenjaeger •
online 1 May 2005
Above: Dendrobium carronii
carronii was considered one of the most difficult plants
to cultivate from flask to maturity. My mentor would always
tell me, "Wet is too wet and dry is too dry." This plant prefers
the dry side but seedlings need a certain amount of water
to prevent drying out. Most of the antelope Dendrobium growers
would caution one to keep it on the dry side but more often
than not, it tends to be too dry and seedlings would end up
as perfected through trial and error and I'm most grateful
to the people who made flasks available for sale in order
for me to try out various methods.
"flasks", besides looking out for the features of well-cultured
"flasks", bear in mind that the maturity of D. carronii is
determined by the size and thickness of the pseudobulbs not
the leaves. Seeing a lot of leaves does not necessarily mean
the flask is matured but it can mean that the flask has not
been replated for a sufficient number of times.
OF A GOOD FLASK
Seedlings should be well spaced apart.
No odd surface growth, such a molds and bacteria, which are characterized
by fuzzy growth or odd
spots of cream, white or green.
Little browning and no bleached plant parts. A few brown leaves
are acceptable especially if the plant is deciduous. If blackening
or browning of seedlings occur en masse, it could mean that there's
contamination within the core - which is not visible until unflasking
If one decides to buy a flask immediately, buy one with matured
seedlings but not those which are too thin and weak looking in
a crowded flask.
Left: View of plants inside the flask.
View of plants from outside the flask.
The old pseudobulbs
of D. carronii usually sheds its leaves after the new pseudobulbs
are formed, for that reason, it is alright to have browning leaves
within the flask as it is part of the growing process. Note also
that the seedlings are spaced apart and there is room for more growing
to take place - but as to when to unflask is up to the grower's
opinion, but I would not keep matured flasks for more than 6 months.
Also note that there are no signs of contaminants within the flask.
If one is keeping the flasks for some time before finding time to
unflask, do check once every few days for signs of contamination
setting in. Sometimes the growth of contaminants can overwhelm
OF THE TRADE
for breaking up agar and to ease the removal of seedlings. It
can be a piece of straight wire, glass rod or even chopsticks.
Just make sure is clean - soak it in disinfectant or heat it
(if it's heat proof)
for trimming off the brown leaves, separating seedlings or
roots. Try not to tug the seedlings but instead gently snip
them. Tugging them may cause unnecessary tears.
for flaming and sterilizing. When flaming cutting surfaces,
do flame until the metal surfaces start glowing - not run
the flame with one swift motion and that's it.
plastic basket for draining the seedlings. It is not wise
too keep the seedlings too wet when working with them especially
if there was no fungicide or bactericide used on them.
a small plastic tub or bowl to rinse the seedlings.
basket tray to place all the tied seedlings in the end.
materials are essential in for this modified method. There
are various tying materials that can be used ranging from
(left to right) hard telephone wires, fine cotton parcel string
or straw strings.
wires are very similar to twist ties but they are smooth rounded
wires without the sharp edges. To use, just separate them
out and cut into appropriate lengths, twist wires to tie.
threads are biodegradable and after some time, they will just
decay and can be removed easily for aesthetic purposes. They
are also water absorbent.
strings are common in Asia and they are used mainly to string
plastic bags to hold food or drinks. It is my personal choice
of tying material (must have rubbed off from my mentor). It
is durable and long lasting - especially useful for plants
that take a long time to root. The only flaw is that they
need to be pre-stretch or else they will loosen after some
time. For this method, I use straw strings cut into 30 cm
lengths and they are stretched after cutting.
moss is chosen as the wetting material for tying seedlings
with. To prepare sphagnum moss correctly, mix just enough
water to wet the dried moss. If you add too much water and
drain the excess, you are in fact removing the substances
that give sphagnum moss its antiseptic properties.
attempt to tie dried sphagnum moss before watering - dried
sphagnum moss expands a lot upon wetting and it may just crush
the seedling or push it out.
Substrates for tying seedlings come in all forms ranging from
artificial to natural. These materials do not break down easily.
use natural cork cut into appropriate sizes using a saw. Cork
is free draining and it does not absorb water easily. It is
rather versatile and easy to shape with a cutting tool.
Styrofoam is an example of an artificial mount. Surprisingly,
plants grow on it pretty well if slabbed on with sphagnum
moss. One can use it straight or use it double-dipped in quick
drying cement. Not all Styrofoam are made equal and some may
contain some substances toxic to plants. Some may also have
some oils that may coat the plants and harm them. When cutting
them with a pen knife, do wipe the pen knife free of oil (well,
the pen knife would rust, so use a normal non-serrated kitchen
Fernroot (Xaxim or tree fern) is another example of a natural
mount. It is a highly nutritious substrate to grow orchids
on and it also absorb water very easily. A draw back for the
usage of this material is that it is very brittle and it breaks
apart easily. It is usually available in the form of a processed
compressed slab. It can be cut very easily with a saw but
I have heard of people hacking it apart with a kitchen cleaver.
For this demonstration, I will be using fernroot slab cut
into 2" x 3" pieces. When sawing slabs, there will be fibres
being sawn out. Do not waste these fibres as they are very
nutritious to orchids. Combine these with a potting mix for
other orchids - terrestrial or epiphytic.