This is a good way to grow onions at home if you don't have a garden or a lot of space. To grow onions vertically all you need is a 5 litre plastic container, soil and onions.
All you need to do is carefully cut out circles in the plastic container. Then, fill the container with layers of soil and onions. Make sure the onions are near the openings, spray water onto the onions frequently and make sure the soil is always damp. Leave in a fairly sunny place.