>>560352What's your climate like? What do you want to grow?
You can start by experimenting with seeds. Go buy some seed, potting soil and small pots at the store and plant them according to the directions on the packet. It's a very cheap investment so it doesn't matter if you fail at first.
Another thing that's easy to grow is citrus. Just take seeds from a fruit(do not let them dry out) plant them in small pots about a centimeter deep and keep the soil moist. They should only take a couple weeks to germinate.