Saturday, July 6, 2013

Orchid Flask Review

Last week, fellow South African orchid blogger David Vaughan, who blogs at, offered to send me a flask of Dendrobium crystallinum to review. I did point out that I was quite inexperienced at deflasking, but he still insisted it was a good idea... Never one to say no to plants, I quickly agreed. David enjoys growing orchids from seed, a topic I am intrigued by, but have never gone through the effort of doing, due to the difficulties of creating the sterile growing conditions and meeting the other requirements (like space...!) for successful in vitro germination and propagation of orchids.

If you're not particularly familiar with the topic, orchid seeds are mostly almost microscopic and dust-like, with little if any "food" in them (compared to the larger seeds of other plants, which have the embryo and a parcel of "food" to give it a head start in life). Orchids take a slightly different strategy - they make millions, even billions of tiny seeds that are little more than embryos without any "food" stored away. So in nature, they have to be really lucky to grow up. What happens with most orchids is a few of the seeds happen to settle somewhere where the right kind of fungus (called an "orchid mycorrhiza") just happens to be growing, and the orchid baby then basically germinates and then steals nutrients from the fungus, which is where it gets the energy to grow big enough to start producing its own sugars from photosynthesis; in some cases the orchid may ultimately give something back to the fungi, but I believe most orchids are quite "selfish" in this relationship, and many seem to keep leaning on the fungus throughout life to supplement their food supply; a few orchids don't photosynthesize at all (so-called "achlorophyllous" orchids) and get all their nutrients from fungi [many plants have fungal partners (mycorrhizae), which they give sugars in return for micronutrients and water; some plants "root systems" end up being mostly fungi; many garden plants will benefit from such fungi and you can buy cultures of them]. Interestingly, the kinds of fungi orchids "team up" with are often pathogenic (cause disease) in other plants. Really young orchid "seedlings" are made up of strange "lumps" of cells called "protocorms" - they look quite unlike any seedling you've ever seen. A little later in their development, the "protocorms" differentiate and produce roots and shoots.

Obviously, growing orchids this way (using fungi) is mostly really hit or miss, so several decades ago, people came up with the idea of giving the orchid embryos everything they need to develop in a sterile "petri dish" (known as a "flask"). Of course, if you put something in a rich nutrient broth, other things are also going to take advantage (bacteria and fungi) so you have to ensure not a single one makes it into the flask with the orchid - which is perhaps the hardest part of the process (of course, getting the growth media right is an art and science in itself...).

Anyway, after that little diversion about orchid seeds, germination and fungi, on to the flask itself!

I asked David to randomly select one of the flasks he'd prepared to send to me. As David asked me to independently "review" the flask, I'll split this up into a couple of sub-sections.

The flask was very well packed, nestled in bubble wrap and packing "peanuts" and arrived the day after he sent it. Once unpacked, the flask was nicely labelled with a picture of the flower of the adult plant, along with the name, and on the back, useful unflasking instructions and of course records of when the plants had sown and been put (replated) into the current flask on the lid. The lid is also well sealed with tape, which should help prevent too much inadvertent contamination, or horror-of-horrors the flask opening in transit. Perhaps it's no coincidence that as someone who cares for living things as a profession (when not mucking about with orchids, he's an aquarist specialising in fish health) David is evidently well versed in how to pack living things for travel!

I took a couple of quick shots when I unpacked on Friday (28 June) last week:
Well packed!
Under the "peanuts" was a nifty construction of bubblewrap
that suspended the flask in transit
Helpful labelling.
Name of plant and picture of flower of this species, Dendrobium crystallinum.
Why, postman, why?
Of course, the post office completely ignored the "this way up at all times" stickers, and the box was handed over to me on its side. I suspect the flask spent some of its journey in the wrong orientation, as the "plug" of medium in which the seedlings are growing was lying at about 45 degrees across the container (it still is as I haven't really had the heart to slam the flask hard enough to dislodge it back into place). The plants seemed unscathed, and the agar wasn't too shaken up. Of course, there is little the sender can do to prevent this sort of thing in transit; I've seen parcels make it through the South African post and even deliveries by courier companies looking like a herd of elephants has used the packaging as a trampoline, so this was relatively pristine! Pictures below are immediately after unpacking.

Dislodged plants and medium - not too bad!
Dislodged plants and medium, other side
I've had the flask in my possession for a week now, and everything still looks great; the flask has been sitting on a seed germination/propagation "heat mat"/germinator (supposedly should keep them at 19) as it is midwinter here, and David suggested they'd prefer being kept more around 18 degrees or above than suffering through the 10 degrees or so the balcony is currently experiencing at night.

The seedlings all look very healthy to me; they seem large enough to make it through the "deflasking" process, and the leaves and roots seem well formed. They'll still be happy in the medium for a little while; I'd like to only deflask when I get to try out a product (AgriSil) I cover below under "tips".

Some shots from today (Saturday 6 July):
Good roots.
Strong, healthy shoots
Healthy baby orchids
It is quite hard to take good macros through slightly cloudy plastic which is all fogged up!

A few of the plants around the edges were looking a little "ragged" - this is either from transport damage or from where they ended up sitting in a "puddle" of water - I've since tipped the flask at an angle to stop this from happening; the damage is quite minor however - and no fault of David's. 

Some tips from David
I discussed the difficulties I'd had with deflasking, most notably with fungi, and David recommended trying a supplement rich in silica to help "harden off" the fragile seedlings; this is a fairly unusual supplement that doesn't seem to have yet made its way into the general gardening realm in South Africa, so is only really availble from agricultural suppliers, who tend to sell it in large volumes. It's not particularly expensive, but the courier costs I was quoted for delivery were outrageous (in the region of 5 times the cost of 5 litres of the product), so I have yet to acquire any. The supplement is called AgriSil K50, manufactured by Plant Health Products, and distributed in South Africa by Madumbi. They also do some very interesting looking "bioweapons" for plant health! The product he mentioned, AgriSil, is basically a solution of Potassium Silicate. Plants use silica to build stronger cell walls - essentially out of glass - and that helps keep out invaders like bacteria and fungi. The dose he recommends is 2.5ml of AgriSil per litre of water adjusted down to pH 6.5 (AgriSil starts at pH 11!); the rinsed seedlings (roots only) are then soaked in this for 12 hours before being potted up in a community pot ("compot").

I'm quite keen to try out this approach, as it makes sense to me. Armour coating an orchid in glass from the inside? I'm in! 

He also noted he'd experienced more success deflasking into (small!) bark chips than any other medium, as he'd also found media that retain a lot of water (like sphagnum) tend to encourage problems with fungi and bacteria. My previous deflasking trials lead to the complete loss of all the cattleyas in pure moss, and I only got 4 out of the one which was mixed moss/bark (bacteria and fungi). Later on some scale moved in and started wreaking some havoc...It's possible I also was too cautious in maintaining high humidity for too long - I left the propagator lids on the plants for many weeks; typical "hardening off" times are apparently more like a fortnight.

David currently has flasks of Dendrobium crystallinum available for sale (presumably only within South Africa due to shipping complications with orchids across international borders), with several other species and hybrids close to being ready. He keeps a list of what is available on his blog at Each flask is about R175 plus postage, and contains roughly 30 plants. It will probably take several years before you see your baby orchid flower, but it's quite rewarding, and if you want lots of one plant (or maybe some spares to share/sell) it's a good way of getting plants, and often a great way of getting unusual plants.Given the sample of this species I've received, I can't say I have any hesitation whatsoever in saying that if he has something you're interested in acquiring, you should get hold of him! It's also often quite interested to raise a bunch of the "same" plant up and notice how much variation there can be in a species or especially a single hybrid cross, particularly in the flowers.

If you'd like to follow these seeds from their "birth", check out these two posts from his blog:

Deflasking seedlings is an interesting additional "angle" to growing orchids; it's not quite as easy as growing many "normal" plants from seed, but most of the hard work is out of the way when you get a flask of seedlings that are ready to be de-flasked and potted up. Give it a go!

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