The Untouchables

Cauliflowers do not like being stressed, this years temps are testament to that. I drape a double layer of debris netting over mine in the hottest periods.

I have also found that watering at ground level reduces flea beetle attacks

I start my seeds in March in plug / cell trays. When big enough & conditions are right ( May) they get planted into raised beds. The beds had a good layer of well rotted manure on them the previous autumn. And dug in a week or two before planting. Also with a treatment of nematodes a few days before planting.
They get puddled in and then stamped in. They are planted along side fellow brassicas and companion plants, nasturtiums, hyssop, thyme, coriander & dill.

I think the Stamping in has improved my results. The last couple of years I’ve had one decent head of cauliflower. But the rest have been half a tennis ball size or like yours gone to seed. But one out of 6-10 plants is still a bit cr@p !

Do you think that it might be too warm for them, I was reading an article earlier that suggested that Brassicas go to seed when the soil is too warm. I'm wondering if we are starting them too late, whether we should be starting off in Feb or early March, to avoid the heat of mid-summer. or maybe even in Autumn to overwinter. I've started some Cauli Seeds in the greenhouse to see if I can get a winter crop or an early spring one.

I'm sure I saw BM had success with mini Aubergines this year, aren't they the crop that wants lots of heat, so probably will do better in a lean-to greenhouse attached to the house and in full sun. That way you get extra warmth expelled from the walls overnight.