Surely you have heard of Regrowing, right? This technique consists of producing vegetables from cores, stems or other peelings.
Grow new vegetables from your leftover lettuce, leek, onion, garlic, shallot or even ginger!
Regrowing does not allow you self-sufficiency but it allows you to see how the plants work. Fun for children for example!
Place your cores in a transparent container filled with water, without drowning them. Change the water daily. Place the pots in the sun, ideally on the edge of a window.
And wait! When regrowth or roots appear, replant in a pot with potting soil.