I have never known a whole lot about plants and how to take care of them. But in the last couple of years I have tried a few things.
These are Japanese Plums. My husband brought home seeds from a few plums he found and ate at work. He told me to just "throw" them in some dirt and see what happens. Be careful, though; he didn't know the seeds are poisonious.
This is an avacado plant. Take an avacado seed; clean it thoroughly. Place 3 toothpicks in the seed near the rounded end. Place the seed on the top of a jar or glass and fill the it to the top with water. Keep it full of water, covering the seed. It has taken 3 weeks to a month to germinate. The seed will crack and roots will come out of the bottom. Soon enough the plant will grow from the top. Once it is about 3 inches tall, transplant to a pot with soil.
This is a pineapple plant. (DUH!!) After you have cut off the top of a pineapple, place it in the ground, with the leafy top showing. It has taken 3 years for our first pineapple....this is what you see.