My cucumbers are not turning green; they are staying white, then yellow. You mentioned a yellow cucumber may have a deficiency.
I answered this but it didn't show up. Do you have them planted in full sun? They require it. The only other answer I can come up with is that there IS indeed a white cucumber. If you purchased regular green cucumber seed, this could be a labeling error. Have you tried eating one while it is in the white stage? You may be pleasantly surprised?
Are they in full sun? They are sun lovers. Only other answer I can think of is that there are white cucumbers available. Could be a packaging error if you bought what was labeled as regular green ones. Have you tasted any of them while in the white stage? Might be worth a try.