i finally got my act together to post some quotes about hot water soaking.
i found several sources siting it and that's why i decided to try it.
the last one (and the first here for those who prefer to watch :)) :
british gardener on youtube...about 1 minute in: he dunks for 20 sec in boiling water
https://www.youtube.com/watch?...
in english, but seems to be a Russian site: quick scalding and long soak in thermos!
https://floristics.info/en/gar...
Canna seeds have a very hard shell that must be softened before sowing. Scald the seeds with boiling water and keep them in a thermos with warm water for 3-4 hours
this one is a pdf...with informative pics of seeds with a little lid that pops after dunking
to allow water in (same as filing, I guess): soaking for 1 min! in boiling water
http://admin.ipps.org/uploads/...
Another example of a temperature-sensitive water gap structure is the imbibition lid that forms in Canna seeds after being submerged in boiling water for 1 min (Fig. 2). The lid separates from the seed again allowing water to enter the seed.
...there's more about imbibitional lid :O...(new word!)..
There is a roughly circular spot on the seed called the "imbibition lid" near the hilum slit (the scar where the seed was attached to the fruit), which is slightly raised above the surface of the seed. The imbibition lid is the spot that naturally decomposes, falls off, and allows water to enter the seed. If you can find it, the imbibi-tion lid is the best place to scarify canna seed.
An alternative to scarifying the seed is the hot water method. Place the seeds in a cup and pour very hot (nearly boiling) water over them. The temperature shock causes micro-fissures in the seed coat which al-lows imbibition. Let the water cool naturally and soak the seeds in it for 24 hours. Warm water above 122°F (50°C) for 24 hours helps to loosen the imbibition lid.
...
unfortunately i don't remember when my lid popped (
)...on the first scolding or after 2nd soak..
but i modified as follows (being scared as i was experimenting):
i waited 1 min after water boiled, then poured about 1/2" of water over seeds, pouring over metal spoon in pint glass jar in order to cool off faster and not break the glass.. left them to cool in jar for 24 hours. had 2 batches: the seeds did not seem to swell ..or just barely..
i also read that the water amount is important: not too much not too little.
so after 2 days since i did not see much swelling i decided to also file off a tiny spot on each. and then 4 seeds got scolded the 2nd time (and left to cool). the second batch (main 7 seeds) i soaked in hot water comfortable to touch.
and continued to keep them all in 1/2" of water until the roots were visible (germination).
as i always do for soaking seeds i added a few drops of 3% peroxide in water (to keep it sterile and prevent bacterial/fungal growth): you don't need to change water, just put a few drops in every day: the little bubbles will form on seeds providing oxygen..and preventing rotting.
as i said before: double boiling dunking did not damage the seeds, the roots grew 5 days ahead of the other batch, but the leaf growth stalled: of 4 only 2 are showing first leaves, while in the other batch i have 2 largish leaves on each on 3 seeds and 2 more starting up.
i am planning to grow them only in pots (and not too big) on my balcony to use as shading for other plants.
So if those slow to start seeds will stunt the plants i won't complain, as i would prefer to keep them smaller. but it's too early to talk about that..we'll see if they catch up or not.
now i am ready to pop 3 champions into tiny pots by themselves.
the other note for those who do not dare to scold the seeds: they need to be on a heat mat and moist until sprouting (read that best for canna to keep them flooded while on heat mat).
quote:
The soil temperature range should be 80 - 90° F. and there must not be much variation in this.
Most varieties of slow germinating seeds will turn black and rot if
there is not sufficient heat in the soil (75 to 90 degrees F for most species) or if the soil dries out or is allowed to remain too wet, which will encourage the growth of one or another of the varieties of fungus or mold.
i hope that this info is useful for future sprouters :).
