According to this piece of research sulforaphane content in broccoli may greatly vary & is always much lower than it is in sprouts.
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum
Evaporative light-scattering analysis of sulforaphane in broccoli samples: Quality of broccoli products regarding sulforaphane contents.
Dr Talalay who ,several years ago sprung the research on broccoli, identified broccoli varieties with superior content & participated in a commercial enterprise to sell them. Some US companies also sell the sprouts or equipment to grow them at home.
I recall a study showing that warming broccoli at 60 degrees Celcius for about 10 minutes maximizes sulforaphane release.