[yankieGirl]

Why don't my brussel sprouts ever tighten up into little heads.  They just spring leaf-like from the stalk.

[Sylvia]

Sounds as though you don't plant them firmly enough. You really have to put your heel into them hard. Also if your garden is exposed it can be caused by wind-rock. You may need to stake your plants.

[Plantoid]

Why don't my brussel sprouts ever tighten up into little heads.  They just spring leaf-like from the stalk.

 If your here in the UK it's down to the fairly unseasonal mild weather .
For a couple of months nearly most supermarkets & green grocers stores have been stuffed full with massive loose leafed brussel sprouts that should have only just been coming to a maximum golfball size in time fro christmas day lunch .

Sprouts like cooler but not frosty conditions once the plants have got about six or more leaves , they also don't need too much rain .

Planting them out in fresh manured soil will make for too much nitrogen in the soil so they will also tend to " bolt ".