Lilies: Blooming Rain!, 1 by ferrymead

ferrymead wrote:
Woody, Nitrogen is used to give good leaf growth. It is used up quickly but also leaches out of the ground quickly. So, for best results use a good
N (nitrogen).
p (phosphorus).
k (Potassium also known as Potash) fertilizer.

Your Callas have not flowered because they did not get any Potash which along with the Phosphorus promotes strong roots and flowers.

A good flowering size Calla tuber should be planted with the top of the tuber 4 inches below the soil level. The tubers will not stand being frozen so it seems that yours have been planted deeply enough.

If the low temperatures have not wiped out the leaves then you should give them a well balanced general fertilizer with the N.P.K. Your local garden centre will be able to recommend the correct one for promoting tuber and flower growth. As they can produce their first flowers 6 to 8 weeks after planting any fertilizer that is water soluble would be best as they need their food straight away this year.

Don't be put off if they still do not flower this year as tubers and bulbs set their flowering pattern from the fertilizer given them the previous year.
So, give them some good nutiton this year and next year you should be right on.

It appears that the lack of flowers was because they needed potash more than anything else.

My DH is the technical guru and knows all the growing needs of Callas. We have been growing Calla tubers commercially for over ten years so I had him check out the message above. I hope that you will be able to pick some of yours for a vase this year.