Sorry If I am repeating myself but a posting earlier has not appeared,
(may be finger trouble?)

I have a Canna that I bought in a pot that has flowered wonderfully but
I may have missed a dead head as now there is a large seed pod on the
plant.

1) Will the seed be viable?

2) How long do I leave it on the plant to ripen?

3) When do I sow it and in what medium & conditions?

Thanks