[shokkyy]

How do commercial growers produce calabrese with such a big head? This year I did Ironman, which I read was a variety used by a lot of commercial growers, and whilst it has produced some very decent heads they're nowhere near the size of the ones in the shops. Is it just a chemical thing?

[Trillium]

It usually is. Many growers add fertilizer to their irrigation lines so the plants get both regular moisture and feed at the same time.

[m1ckz]

i put in   speedy seeds callabrese,up to 5in across is ok,,,any longer they blow,,,so i cut them at 4ins   nice too

[the Kergan]

Your lucky to have heads at all. Mine are blooming useless no heads at all and still very spindly looking

[Trillium]

Bigger isn't always better when it comes to taste. I'd sooner have smaller tasty ones.

[m1ckz]

i think these were called    sukura...give them a go,got them from ebay

[shokkyy]

The Ironman are giving me nice heads, better than I've grown before. I didn't do a very good job of staggering them though, as I've had to cut six heads in the space of a week.  Much as we like calabrese, you don't want to eat it every night

[allotment-bill]

i grew Monaco they formed lovely big heads and not overly strong flavour grand children love this one   

[SnooziSuzi]

The best ones I ever grew, which were as big, if not bigger than the supermarket ones, were a variety called Parthenon from Kings Seeds.

[galen]

The best ones I ever grew, which were as big, if not bigger than the supermarket ones, were a variety called Parthenon from Kings Seeds.

Although a different supplier that's what I'm growing this year - SnooziSuzi your reputation is now on the line... 

[Ivor Backache]

I grow F1 Marathon. Always had good results.
I grow them like cauliflower. When the seedlings are established I pot them on and when established again I repot them.  I take them to the allotment in 6" pots and never let their growth be inhibited. Handful of poultry manure and fill the hole with water.

[SnooziSuzi]

I've equally always had good results with sowing them in modules and planting out at the 3-5 leaf stage and let them fend for themselves (except for watering when necessary and hoeing any weeds around them)