The answer may surprise you! We provide regular lawn service to Colorado lawns from April 1 - October 31. The fall can produce very good growth due to the cooler temperatures and additional moisture that is normal during this season. Leaves that start to fall get vacuumed up with routine service so that they do not kill the grass. It doesn't take long with them sitting on the turf to do some damage. Towards the end of regular lawn service, we begin fall services and normally get the majority of those services done by Thanksgiving Day. Shortly after that is when we close down for the winter. We re-open again in the Spring on April 1st.