So my parent in law wanted to grow some edible plants in our backyard. We have a pretty big backyard and we have been putting all kinds of chemicals on it. We have used grass feed, moss killer and rodent repellent. (Repellent that occasionally kills gopher and mole) I am pretty sure that my lawn is unsafe to grow food to eat. How my question is: is there a way for us to prepare an area of our lawn for them to grow these edible plants? Buying enough soil from home depot to grow food seems to be an very expensive option. Any advice?