This is the result of an unintended test. Both plants were grown in mineralized soil (but without much N added) which had just yielded a very nice crop of tomatoes. The one on the left received feathermeal at about a 200 lbs/ac N rate, a dusting of gypsum for sulfur, and borax at a 2 lbs/ac Boron rate. The one on the right, grown just 6 feet away, didn’t receive any of these amendments between crops, as there was still a tomato plant growing there. I think this illustrates two points; first that proper mineralization can produce outstanding heads of broccoli. Second, that all the minerals need to be in place for this sort of result. Everything else can be in the soil, but a good dose of nitrogen with a bit of sulfur and boron can make a huge difference. My guess is that without all the other good gardening practices like composting, expert watering, mulching, and weeding neither plant would have succeeded.
This is the largest head of Brocolli I have ever grown. These seeds are from Fedco seeds in Maine. We bought the seeds because it produces unprecedented side shoots, so the whole story may not yet be told.
The description is here: http://www.fedcoseeds.com/seeds/search.php?listname=Broccoli&cookies=no&item=3313&index=5
You can see how mineralization helps cheer up the gardener…