planting pots from seeds

[scorpio]

I am a complete idiot when it comes to gardening, I have planted some seeds in pots and have a lovely foliage but no flowers, ( Although I know you dont get actual flowers) The same plants in my local garden centre has the same foliage which look like a real cabbage which are beautifull and thick and hardly any foliage around the centre part Can anyone tell me where I am going wrong, The plants are ornamental Cabbages.