Please let us know where you live, so we can suggest plants that are good for your area, and we can tell you when to plant them.
You can grow gobs of stuff in an 8x3M garden. The next question would be - what do you like to eat? If you hate tomatoes, then I would not suggest growing those.
Tomatoes are one of the most popular garden plants, because a tomato of the vine beats the pants off a grocery store tomato any day. Peppers are also easy.
I also grow beans, peas, squashes of all sorts, carrots, beets, broccoli, eggplant, onions, potatoes, shallots, assorted herbs, artichokes, corn, and more.
