I can't figure out why mine won't sprout this year. I'm in USDA Zone 6B. I overwintered them indoors then put the pots back out. It is now Oct 8 and nothing came up. I just upended one pot and was surprised to see 10 little bulbs, looking firm and good but no hint of a sprout. 1/4" to 3/8 estimated diameters.

The pot contained largely organic matter. Moist from recent rains. No hard soil.

I can only attempt to grow them in pots because of the voles.