Broccoli not forming heads

[Ricardo]

I've tried broccoli for the first time this year and all looked to be going well at first. However, now the plants are about 1m tall with thick, healthy looking stems, but they don't seem to want to form heads. (Dunno if that's the right term). One only had formed a loose head, another one formed a head which immediately bolted.
As for the rest - nothing.
I've been watering twice a day, particularly through that hot spell in June, but nothing seems to be happening.
Is it too early to hoik them out?
What could I have done wrong? I prepared the ground by digging a couple of troughs and putting manure in before covering over, I started the plants off in the greenhouse then planted out in the prepared soil.
I've never tried brassicas before so I'd appreciate some pointers/do's and don'ts from you knowledgeable lot so I can hopefully get better results next year.

[Two_Sheds]

so is it calabrese you've got?


or (purple sprouting) broccoli?

[Ricardo]

Calabrese - the "normal" kind. I thought start simple....

[Two_Sheds]

Did you plant them into REALLY firm soil (concrete would be about the right level of firmness)

[Ricardo]

Doh - no, just planted them as normal and watered them in. Same as just about everything else. So that's the mistake I made then? From your response I'm assuming they need really hard compaction around them to grow properly?

[rustylady]

Firm soil is really necessary for brassicas, and I also think you've been watering them too often. You shouldn't need to water anything twice a day unless it's in a small pot.

[kathyd]

My calabrese only had small heads on it too Ricardo, as did various other people's. What them lot ^^ say is obviously correct, but I'd like to feel able to blame the weather again, at least in part, as with so many other things - it makes me feel so much better . If/when you get a head, chop it off and wait for the side shoots to grow from the leaf nodes below it - you'll probably get more from those than from the main head this time. Personally I'm planting more sprouting broccoli in future - I got loads more to harvest from them, and they spanned weeks and weeks!