Mini veg?

there are lots of mini veg seeds on the market these days , when i moved house and gave up my plot and was on a waiting list i planted everything in a 40x40 gravel garden in pots or oblong planters or grow bags , but a good tip is dont sow to much at once of each item , let first batch come up and start growing then sow more

Are you on commission Auntiemogs? 

I can grow mini veg from just about any seed. My favourite last year were my mini beef tomatoes... which came out tomato sized! 

hundreds and thousands tomatoes in hanging baskets worked well for us, the tomatoes were grape sized, but they just kept going. (hundreds and thousands of them).
Grendel

I also grow everything in pots on a balcony. I have found that growing normal veg is mainly fine and find the mini veg seeds overpriced.
Things that have grown well for me in pots are all salad veg, peas, broad beans, french beans, carrots, parsnips, kale and cabbage
I don't bother with potatoes and onions anymore - they do grow but the yield you get even from a small pot is not really worth it.
Soft fruit also works very well - currants, raspberry canes, strawberries.
You also get a suprising amount of fruit from minarette fruit trees - I have a plum, apple and peach and end up with more than I can possibly eat.
I would second the suggestion of water retention crystals. Even with these I need to water every day in the summer.
Good luck!