Extension News

A Great Lawn Begins in the Fall

Note to media editors: This is the Garden Column for the week of Oct. 19, 2007.


By Richard Jauron
Iowa State University Extension

Fall is a busy time for gardeners.  With so much to do, lawn care is sometimes neglected.  However, proper lawn care in fall helps ensure an attractive, healthy lawn next season. Important fall lawn care practices include mowing, fertilizing, controlling broadleaf weeds and raking.

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 2.5 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 4.5 inches. 

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. 

Broadleaf Weed Control
Fall (mid-September through October) 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. 

Effective broadleaf herbicides include 2,4-D, MCPP, MCPA, dicamba, triclopyr and others.  The most effective broadleaf herbicide products contain a mixture of two or three herbicides, as no single compound will control all broadleaf weeds. Broadleaf herbicides can be applied as liquids or granules. Before applying any herbicide, carefully read and follow label directions. 

Turfgrass plants use 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. A thick layer of leaves (little or no grass is visible) will need to be raked up and removed. A thin layer of leaves (areas of grass are clearly visible) can be shredded with a mower and left on the lawn. After mowing, little leaf debris should be visible. 

Fall is a beautiful time of year. It’s also a busy time for gardeners. Make sure that you take time out of your busy schedule to properly take care of your lawn this fall. The reward for this fall’s efforts will be an attractive, healthy lawn next year. 


Contacts :

Richard Jauron , Horticulture, (515) 294-1871, rjauron@iastate.edu

Jean McGuire , Extension Communications and Marketing, (515) 294-7033, jmcguire@iastate.edu