I've been watching your experiment with interest. Thank you for the update.
A generous trader gifted me with Canna seeds some years ago. Having no idea how to germinate those things that looked suspiciously like Boston Baked Beans, I tried the scarify-and-germinate-in-water method (pot up after the radical emerges) I found in various GW posts. It worked flawlessly, so I've been using it ever since. Putting the glass next to the bathroom sink makes it easy to remember to change the water twice a day. The method worked nicely for the Canna patens seeds Domehomedee sent me last year (30 out of 33 germinated right away). I haven't tried winter sowing Cannas, but they do volunteer in unexpected places around the yard most years.
Maybe I should try adding H2O2 next year...
