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Despite green summer lawns, time to think of fall fertilization

Media contact:

Robert E. Thomas
Information Specialist
University of Missouri Cooperative Media Group
Phone: 573-882-2480
E-Mail: thomasr@missouri.edu

Published: Thursday, August 20, 2009

Story source:

Brad S. Fresenburg, 573-442-4893

COLUMBIA, Mo. –It’s not too early to start thinking about fall aeration and fertilization.

“Everything may look green, but don’t be fooled. We still have August and September with possible heat and drought,” said Brad Fresenburg, University of Missouri Extension turf researcher.

Aeration is the practice of pulling soil plugs to allow better air and water movement. Aeration reduces compaction and thatch. It can be done in spring and fall.

“Applications of fertilizer after aeration will move nutrients immediately into the root zone of your lawn,” he said. Aeration equipment is available at local rental stores or garden centers.

A machine that pulls a half-inch diameter plug 3 to 4 inches deep on 4-inch centers will do an excellent job. Machines that force hollow tines into the soil are better than the pull-type drums with tines, he said.

Start fall fertilization with a soil test to learn the soil pH and information about lime requirements.

A soil pH between 6.0 and 7.0 is acceptable. Soil pH between 6.4 and 6.8 is optimum.

MU Extension guide G6954, “Soil Testing for Lawns,” provides information on how to submit soil samples to the MU Soil and Plant Testing Laboratory. Find the guide at extension.missouri.edu/publications.

Many organic fertilizers such as Organica, Milorganite, Sustane and Ringer provide an excellent source of slow-release nitrogen. Organic fertilizers require soil microbes to release nutrients, so the rate of release will decrease as soil temperatures decline by late fall.

Inorganic fertilizers have much higher amounts of nitrogen and are quick-release, lasting a few weeks.

Use fertilizers with nitrogen, phosphorous and potassium in a ratio of 3-1-2, Fresenburg said.

Check the label to find a product that is 30- to 70-percent slow-release nitrogen.

For best results in fall, apply 2.5 to 3 pounds of nitrogen per 1,000 square feet. Divide amounts over two or three applications.

Soil test results indicating high to very high amounts of phosphorous and potassium may require applications of fertilizers with nitrogen alone.

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MU Extension publication G6954, “Soil Testing for Lawns,” is available for purchase or free download at extension.missouri.edu/publications/DisplayPub.aspx?P=G6954.

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