This article was written and submitted by Alannah Sperr, UMN Extension intern, Wright County
In Minnesota, we can usually expect fall to come at the end of September or beginning of October. Fall freeze dates can start as early as September 22, which means the air temperatures drop to 32 degrees. Snowfall in Minnesota can be expected as early as October. As homeowners and gardeners, it is important to know how and when to take care of your lawn during all seasons. As fall approaches, many people stop their lawn care regimens; however, fall is the best time for lawn care and there is a lot of work that needs to be done to prepare your lawn for the long winter.
Our cool season lawn grasses actively grow when air temperatures are between 55 degrees and 75 degrees. As the temperature begins to cool below 55 degrees, grass growth will slow significantly and you can stop mowing. Keeping short grass before winter comes is also known to reduce vole damage to your plants. They are less likely to nest in the short grass where they are more visible to predators.
Aerate your lawn
Fall is a great time to aerate your lawn. Aeration is a mechanical process that involves pulling out soil cores to reduce soil compaction and allow for air, water, and nutrients to penetrate the grass roots. Aerating your lawn helps the grass roots grow deeply and produce a stronger, healthier lawn and provides better seed-to-soil contact when combined with overseeding.
The optimal time for aeration is late August to mid-October because most weeds are not actively germinating. Spring is the second best time for aerating your lawn, but you may encounter more weed pressure as weed seeds are exposed to light. Aerators may be rented or purchased at many lawn care or home improvement stores.
Might need to dethatch
Another lawn care practice that some people practice in the fall is dethatching. Thatch is the accumulation of roots and shoots resistant to decay beneath the healthy grass of your lawn. Dethatching removes the thatch Consider dethatching your lawn if you have more than 1 ½ inches of thatch. If less than 1½ inches, it can be left alone.
Dormant seeding for next spring
Dormant seeding is also a great practice for fall lawn care. The idea is that grass seeds will remain dormant through the colder months and then start to germinate as soil temperatures begin to warm up. This will prevent you from having to seed in the spring when the soil is still wet and cold. The best time to practice dormant seeding is from late October through mid-November.
Fall is a good time for weed control
Lastly, remember that late September through October is the best time to work on weed control. Spraying for weeds in the warmer summer months increases the chances of damaging your lawn.
By setting aside a little bit of time in the fall to dethatch, aerate, and seed your lawn, you can help your lawn through the winter, and have it come back even better in the spring. For more information and details about these yard maintenance tips, check out the links below:
Controlling Thatch in Your Lawn: https://extension.umn.edu/lawncare/how-control-thatch-your-lawn
Dormant Seeding: https://extension.umn.edu/lawncare/dormant-seeding
MN Lawn Care Calendar: https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar
Overall Lawn Care: https://extension.umn.edu/lawns-and-landscapes/lawn-care