(status. last rev. October 2019, believed finalized, what else is there to be said?)
Misery you may run into when sowing on cotton fiber ... Watch out for it!
Pictures below ... Click the pictures for full size view!
Lately there has been a lot of fuss, on media like youtube, by reviving and making an hype of an old seed testing method that was used to check seed germination rates. All of a sudden this has become the sanctifying method for sowing seeds of "difficult" seeds/plants. Blown into holyness without performing any miracles! There is, however, nothing new about it. I used and tested it 40 years ago.
It involves sowing seeds on a presumed "inert" support like "cotton wool" or "paper towels" where originally laboratory filter paper was used. (The size that fitted directly into a petri dish, and possibly using more than one layer! I still have a stock of both! LOL!)
The original method was used as a method to estimate seeds quality by doing a germination count after which the whole set was discarded. Different liquid conditions were used to assess germination rates. (Prof Norman Deno uses a similar method to germinate all sorts of seeds in the presence of GA3, gibberelic acid, using paper tissues in a zip-lock bag moving germinated seeds to soil right after germination.)
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| Petri dish sowing |
Now it has been promoted as a method of choice for a "long term" sowing environment. But one needs to know about what can happen!
First of: the support is not "neutral" nor inert. Paper towels can be impregnated with all sorts of stuff including balsam to cure your running nose. Cotton pads are treated to make them maximally hydrophylic aka absorbing water at maximum.
Those supports will NOT prevent any sort of germs to develop if they are dragged in together with the seeds. I've seen test pads with seeds being overgrown with fungus crusts within days. Game over, unfortunately.
Be aware that true cotton fiber and paper towels are made of "cellulose". Upon decay these will be supports of choice to harbor lots of fungi. Your juvenile seedlings may suddenly be under attack!
Be aware that "cotton wool" today is anything but cotton! Mostly they are made of (cheap) synthetic fibers they do NOT decay nor dissolve. In fact, if seedlings are left for too long in that medium it may become impossible to remove the fibers and they may strangle the foot of the plants. (see pictures)
If attempts are made to remove the Lithops seedlings in time it may result in huge losses. The reason is that Lithops, quickly, do send out that central tap root and that is getting incrusted in the cotton. Trying to remove or tearing seedlings out of it may be the cause that the central root is getting ripped off, staying anchored in the cotton fiber. Seedling = RIP.
Does this mean that one cannot use this method? Of course you can ... but you should know what you are in for, especially as IMHO (*) there is absolutely no advantage over classical sowing in "normal" soils. (see under Sowing )
(*) IMHO = In My Humble Opinion
Look to what you may end up with in the best of circumstances, that is if the plants survive and you did not rip off the root + growing point getting them out of the "synthetic" cotton fiber!
Many thanks to Nadja K. Tronjberg.
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