By Richard Jauron, Greg Wallace
Fall’s arrival brings a natural question: Even though the weather has turned cooler, how does lawn care and preparation change? Colder weather doesn’t mean lawns should be ignored. Rather, there are plenty of ways to prepare lawns for the winter ahead and optimal performance next spring.
Here are some tips from Iowa State University Extension and Outreach horticulturists on how to handle fall lawn care. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or hortline@iastate.edu.
When can I stop mowing the lawn in fall?
Continue to mow the lawn until the grass stops growing. The foliage of Kentucky bluegrass and other cool-season grasses usually stops growing in late October or early November in Iowa. Mow Kentucky bluegrass lawns at a height of 2½ to 3 inches in fall. When mowing the lawn, never remove more than one-third of the total leaf area at any one time. Accordingly, a lawn being mowed at a height of 3 inches should be cut when it reaches a height of 4½ inches.
When is the best time to control broadleaf weeds in the lawn with a broadleaf herbicide?
Fall is the best time to control perennial broadleaf weeds in the lawn with broadleaf herbicides. In fall, perennial broadleaf weeds are transporting food (carbohydrates) from their foliage to their roots in preparation for winter. Broadleaf herbicides applied in fall will be absorbed by the broadleaf weed’s foliage and transported to the roots along with the carbohydrates, resulting in the destruction of the broadleaf weeds. Spring applications are not as effective.
Is fall a good time to fertilize the lawn?
Fall is an important time to fertilize the lawn. Spring and late summer fertilizer applications mainly stimulate leaf growth. A fall fertilizer application promotes root development, enhances storage of food reserves and promotes early green-up next spring. Late October or early November (once the turfgrass foliage has stopped growing) is the ideal time to apply fertilizer in fall. Nitrogen is the most important nutrient to apply in fall. Apply 1 pound of actual nitrogen per 1,000 square feet.
Do I need to rake the leaves on my lawn?
Turfgrass plants utilize light, water and nutrients to manufacture food. In fall, lawn areas beneath large trees are often completely covered with leaves. The leaf debris prevents the turfgrass plants from manufacturing and storing food prior to winter. Additionally, the leaves of some tree species mat down readily and may smother the grass. Thick layers of leaves should be raked up and removed. Small amounts of leaf material can be shredded with a mower and left on the lawn.