Supermarkets are overflowing with broccoli at the moment, but the actual "natural" growing season for broccoli is during the summer months. The heads of broccoli sold now are either from storage or grown in hothouses. Not that there is anything wrong with that, but sometimes the taste of the vegetable isn't the best.
It's interesting that broccoli is hitting the stores now because now is actually the sprouting season for it. This past weekend I visited the home center to pick up some pots for my tomato seeds and found broccoli seedlings for 100 yen apiece.
I'm learning as I go with broccoli, but there seem to be two main types sold in Japan. The first is the large head broccoli which is the most typical type found in stores. The other is called stick broccoli which instead of accumulating into one large head spreads out into individual stems. In the U.S. I've seen this sold as Chinese broccoli or Gai Lan.
Stick broccoli can be harvested continually as the stems reach the right size. This makes it all the more cost effective. Interested, I picked up one seedling and transferred it to a larger pot.
According to the instructions on the back of the label, moderate watering and lots of sunlight are all that is needed. Hopefully by June I'll have some delicious broccoli!