I have collected few varieties of canna seeds this year. In my zone what is the best time to sow them, fall or spring?
Also what is the best method of sowing them.
Spring. Late winter would be okay if you germinate the seeds in pots and keep them in a sunny window sill or otherwise provide sun and protect them from freezing until the soil in the ground warms up.
When you're ready to do it, use edge of a file to scratch a little nick in the outer shell of each seed on the side of it. That will allow water to get in and speed up the germination. Then, soak the seeds in a glass of water for a couple of days. After a day or two, you might see a white radicle, or rudimentary root begin to emerge from some or all of the seeds. That means they are germinating. Take those out and plant them in pots.
If you don't see the tips of the radicles yet, you would at least hope to see that the seeds have swollen a little. Whether they have begun to germinate or not, I plant them in pots after a maximum of three days in the water. Unless the seeds are dead, they will germinate.
Don't leave them in their first little pots too long. When the soil has warmned up, put them in the ground or into larger pots.