Container Gardening, that is, growing plants in containers instead of planting them in the ground is the ideal method for terrace top gardening. The size and shape do not really matter. Any scrap container can be used productively. Capsicum, Tomato, Brinjal and Chilly are the easiest to grow in a container.
Container Gardening Tips
When soil becomes too wet the roots of plants can rot. The hole at the bottom is very important.
Don't combine plants with different needs, some of them will not thrive.