Billy said

Cut the heads while they are still tight and dark coloured,
before the flowers start to open. More will grow from lower
down.

David

. . . and mulch like crazy to keep the ground cool.

...makes me think planting brocolli in raised beds might not be a
good idea? I thought early soil warming was one of the "benefits"
of raised beds. Any thoughts?

It's a cool weather plant (spring & fall). Maybe try starting it in
March next year. Where are you?

Indiana.

I tried starting brocolli seedlings, 20MAR, on my own. I didn't use any
grow light so they were - well, wimpy. They are now long since
transplanted to the garden but I think they are too late.

My more successful brocolli plants were two store-bought plants. These
already had some spears when purchased. These are the ones producing now.

I also bought some smaller ones 23MAY, they are progressing fine but I
fear also too late. Again, I'm new at this brocolli stuff ...

I'm really looking forward to late summer, I'm ready for another swing.

Not that the spears I'm getting now aren't great! They are just spears
only a gardener could love. ;-)

I'm just loving this gardening thing. All the help from this group is
greatly appreciated!