What vegetable grows better in wooden box for balcony?

Mexican oregano is a very Harty plant, it does well in sun or shade. It is an evergreen so it will have nice woody greenery year round, the purple flowers on the top are very aromatic and can be used for dried flowers, wreaths etc.

Rosemary is also the same and has medicinal uses,.

There is not enough room for vegetables ,try making it a herb garden.

Try lettace. I'm growing 5 type plus spinach in two pallets. They are only 3-4 inches deep

2x4 inches or feet/meters? radish, baby carrots,lettuce, spinach if measure is in inches......if measure is feet... there are more options-there are planting guides out on the internet. 2 ft wide, 2 ft deep 4 ft long would take 2 of the smaller tomato plants, if you don't know if the wood has been treated with chemical preservatives, line the box with with mulch film then plant.

Any herb you wish, pepper plants, any variety of chili pepper, small tomato, lettuce, spinach. What do you like to eat? You might even get a small cabbage, broccoli or cauliflower if the boxes are deep enough.