Depth decides almost everything. Leaves need very little, roots need a lot, and fruiting plants need a big reservoir of water more than they need soil.
From this range, the ones that do well in pots are Lettuce Mix and Lettuce Romaine in as little as 15 cm, Giant Spinach and Chard Green Broad in 20 cm, Red Beet in 25 cm, Carrot Chantenay in 30 cm — it is a short-rooted variety precisely for this — and Green Peas Petit, Tomato Red Cherry and Cucumber Supermarketer in the biggest container you can lift, with something to climb.
The ones not worth the trouble are the brassicas. Broccoli Calabrese and Cabbage Purple want firm ground and a long season, and a pot gives them neither. Turnip Purple Top is borderline and rarely worth the space.
The failure mode is always water. A container in July dries out in a day, and a crop that dries out once bolts, splits or stops. Water in the evening, mulch the surface, and use a bigger pot than you think you need.
