I am a preservice teacher at the University of Northern Iowa. A garden can be great for young children. We actually have a garden at the preschool I have spent time in the past few years. Students are able to learn about what plants need to grow and they also get to taste test their edible plants in their garden! They also get to cook, using there edible plants, in their garden. A garden can connect to a variety of content areas. There have not been many problems but the students know what is expected of them when interacting with the garden. It is important to have class discussions about the garden. I have never used it for teaching about planets but I think that would be a great lesson on how things grow!