Mowing: Assuming you allowed turf to grow to 3-3.5”, slowly begin reducing height of cut to prepare for winter. Finish the season at approx. 2 inches high. Grass that is kept long over the winter promotes snow mold in the spring.
Soil Amendments: Most soil amendments can be applied until the ground freezes and/or leaves fall. Apply based on soil test results: lime (calcitic or dolomitic), gypsum, humates, etc. Avoid the application of excess N application in late fall to help harden off the turf for the winter season and avoid diseases that can occur under cold weather conditions on lawns and athletic fields that have not had the opportunity to appropriately harden off.
Turf Blankets: protect athletic fields from harsh winter conditions and promote faster growth and green-up in the spring. With the use of turf blankets late season repairs and seeding are still possible creating an environment that keeps the soil warm.
Leaves: mulch leaves while mowing to add valuable organic matter –carbon – for as long as practical. After that mow and bag (or tarp) removing all leaf litter before the snow. Leaf litter harbors fungi and promotes disease that can damage the grass and plants. One caution, make certain that you are not mulching Maple leaves that may have a fungal disease like Tar Spot. It is best to rake and destroy these leaves rather than using them in the mulch where the spores can overwinter and re-infect the Maple leaves.
Make Notes for Spring: note any troubled spots so you are ready to top dress, over seed and budget for it in the spring.
Equipment Maintenance: while it’s easy to think you’ll get to maintain the equipment over the winter it usually doesn’t work that way. So at a minimum when putting your mowers, blowers and trimmers away for the season drain gas lines, check fluids, sharpen blades and clean off debris from the season. If you’re a little more ambitious change the oil, replace sparkplugs and fuel filters. This will make getting going next season a lot easier.