http://www.planetnatural.com/site/xdpy/kb/growing-cauliflower.html

It's a very picky plant ... Successful cauliflower growing requires regular continuous growing conditions. Any stress to the plant will result in a reduction in head growth which is often known as 'Buttoning'

Is it anywhere near where someone might have been spraying for weeds? Especially a lawn? It looks suspiciously like damage from 2-4-D, a common weed killer. you might also have waited too long to harvest, and it started to bolt, but that usually is straighter and more normal looking, if still not really edible.

Kevin : )

First timer w/ caul...Any ideas why my heads turned out looking "dirty", grayish, not clean white. I did the leaf tie up thing w/ string, maybe too late? Maybe due to heat waves? They taste ok, but not appetizing look...OOps, I am in CT, not OK, but any advice good/