Did you let them go dormant over the winter?
I've noticed with mine that if I don't make them go dormant for at least 6-8 weeks they don't bloom.
Hope it helps

maybe bloom fertilizer 15-30-15 would help.

Yes, they were allowed to go dormant all winter here in Michigan, a good 4 months.

I have some 30-30-30 I could try but that may be a bit much unless I dliute it.

had two lovely pots of calla lillies that bloomed and grew like crazy last year. They both started growing cones on some of the flowers, so I though "hey! They pollinated each other!" I let the cones grow and isolated the seeds, but they wouldn't germinate. I figured the seeds were serile, but I went ahead and dug up the bulbs for storage anyhow. I just took them out of their wood shavings an they seem smaller, but firm, and a couple even had little green shoots about 1 cm long comming out. I started them in little containers and put them on a sunny windowsill with a bit of fertilizer and water.
Is it posible that thses bulbs will flower for me this year or even sprout? I'm worried that because I stupidly let them go to seed, they have no energy left. can I improve my chances of flowering with a bloom building formula?
Thanks!

Hi most calla lily will go to seed after the flower falls off it will bend over and tough the ground that when the seed is growing leave it as long as possiable on the stem then bring it in the house and let it dry for about 4 months then plant it and give it lot of light it will take about month before you see little shots they look like blades of grass i have been growning calla lily seed for 3 years now remember it take at least 2 to 3 years to get flowers even if you take a small bulbs off the mother you will only get the flower in about 3 years good luck Anna