That's bad. Your plants have experienced stress. The broccoli will make a smaller head, but side shoots should be fine. Stressed Cauliflower, in my experiece, will not make a quality head. Go ahead, tho, and harvest a small head before it starts splitting up.

Brook

Agreed. Cauliflower is one of the least forgiving crops. Unfortunately, once it's stressed, you can pretty much kiss any hopes of a decent size curd goodbye. The resulting small head of a cole crop is called "buttoning". That being said, as was already, suggested your broccoli will give you side shoots for the life of the plant, but cauliflower just doesnt work that way

I think it's the broccoli and not the califlower, the heads looks like little broccoli. The plants are doing well, they look great. I was all happy about the little broccoli, so they will just flower instead of grow?

Early heading is a stress reaction. Brassicas require constant moisture and adequate nutrients for yield and quality. Mulching conserves moisture while also keeping the soil cool. In heat they do best under row cover which reduces the sun exposure. Cauliflower will often yellow if leaves not tied about the head or kept under some cover.

When planted early there remains the chance of a late frost which can also stress the plants. Rowcovers are a good protection and can increase the temperature within the covering.

A soil test will identify nutrient imbalances or deficiencies. A late summer or fall soil sampling alows you to prepare amendments before the spring start of growing season. Soil nutrient imbalances are a major cause of stress, pest and disease occurance. A simple soil test can eliminate your soil as a problem.

Broccoli will live on after beheading, though, and will give you side shoots if conditions improve, give it a chance if you have the room. That little stressed head will probably be bitter.

IME, factors that contributed to less than desirable results on cauliflower & broccoli are cultivar (I find that hybrids produce better than OP cultivars, with Green Goliath broccoli being the only exception), nutrients (as mentioned above), and planting timing (a late season planting results in slow growth and reduced head size).