My wife and I recently purchased a new house in Iowa. The lot size is roughly half an acre, so there is lots of grass that we have to work with. Unfortunately, it is in pretty rough shape. There are several different types of weeds growing all over the place. The most significant weed is crab grass and there are some dandelions and "creeping charlies" all over the place. We also have some mushrooms growing in various parts of the yard as well. I spent a few hours a couple weeks ago hand picking most of the weeds, and when we returned from a vacation a few days ago we are right back to where we started. We have a 16 month old baby girl who loves to play outside so I do not want to use an chemicals in our lawn and want to keep it organic. What would be some advice on where to begin with bringing this yard back to a more healthy, and less weedy, state?