The National Wildlife Federation's 2014 blog post " Leave the Leaves for Wildlife" has gone viral this year on social media and on television. Unfortunately, the qualifier seems to have not been emphasized: "A leaf layer several inches deep is a natural thing in any area where trees naturally grow".  Therefore, the advice not to rake the leaves is about woodlands, not our lawns!  The article goes on to say "Remember, the less time you have to spend doing the back-breaking work of raking up your leaves, the more time you have to enjoy the gorgeous fall weather outside and the wildlife visiting your garden!" Yes, but come spring you will have dead grass to deal with.  This article ended up turning forest management advice into really bad lawn care advice.   Mold occurs when moisture is held in. It is important to try to keep leaves off the lawn for this reason. Keeping the lawn free of debris will help moisture to evaporate and help keep the lawn free of disease and pest infestation.