The selection of the best medium for your purposes can be a frustrating task. Of course, we want to choose the best media for our purposes, and there are several qualifications for what consititutes the
“best” medium. These should be discussed briefly.
What do we mean by the “best” results for orchid seed germination? We want:
1) As high a germination rate as reasonably possible
2) Good growth of protocorms to a reasonable size
3) Minimal progression to larger size such that protocorms are of uniform size, producing better replate flasks
4) Good survival for as long a period of time as reasonably possible to give the flasker plenty of time to replate them
All of these characteristics are important; number 3 requires some explanation for the novice. Although germination may occur quickly, some seeds are slower to germinate or slower to grow than others. If protocorms
mature at the same size and seedlings develop at a comparable rate, replate flasks will tend to have seedlings that are of similar size. Rather than a replate flask with HUGE seedlings and tiny seedlings mixed together, it is more desirable to have finished flasks with seedlings with relatively little variation in size.
Sometimes it is unavoidable, and seedlings will do what they darned well please; Stanhopeinae (Stanhopea, Peristeria, Gongora, and Coryanthes) will often do whatever they want, and flasks will be a mixed bag of
seedlings of different size no matter what is done to the contrary. Other seedlings tend to grow at a surprisingly steady rate, producing uniform crops of Epidendrum or Encyclia seedlings, for example.
Number 4 also deserves some explaining. For those that have not witnessed it, “brown out” is when protocorms turn brown or yellow while still in mother flask- a sign that you did not act fast enough to
get them into replate flask. While there are other causes (high temperatures, for example, for plants that cannot tolerate them), brown-out is often caused by “bad” concentrations of sugars. If you have
problems with brown-out, try our pre-mix of P668 with B852 banana powder. It has less banana powder in it than replate flask, but not so much that it inhibits germination. Good stuff.
The following is a table that describes in the most general terms possible the different formulae that we sell for the germination of orchid seeds. “Western Media” consists of our Western seed germination formulae, W2.5 and W3. P668 is the commercially available preparation from PhytoTech Labs, which we also resell. P668 + B852 is our own homebrew mix that we use here for general sowing.
The following table describes, in the most general terms possible, performance characteristics of these media with different genera. There are always exceptions and the grower is urged to experiment to determine the
best possible formulae for their conditions.
Special note on Phalaenopsis species: We get in a fair number of different phal species, but they almost never germinate for us. I have suspicions that the dry seed does not live very long, so the seed we get is
usually dead. Therefore, I have qualified all of the media as “no data” with this genus. However, P668 was formulated specifically for germination of this genus by Dr. Ken Torres, now at PhytoTech Labs.
It should prove useful to those that need to germinate this species (probably from green capsule).