Horticulture News

DATE: November 12, 2007

HARDIN COUNTY COOPERATIVE EXTENSION SERVICE
201 Peterson Drive
Elizabethtown, Kentucky 42701-9370

BY: Amy Aldenderfer
County Extension Agent for Horticulture

FALL GOOD TIME TO FERTILIZE LAWN

If you want your lawnmower to collect a thick coat of dust next spring and summer, now is the time to begin a simple schedule to accomplish this goal.
Put some nitrogen fertilizer on your lawn this fall and omit spring fertilization. This two-fold approach will give you an attractive green lawn with more drought tolerance and fewer disease and weed problems come summertime. It also generates growth to cover bare spots and freeze-killed crabgrass skeletons.

When applying nitrogen fertilizer in the fall, make two applications about four to six weeks apart. Put down one and one half pounds of actual nitrogen per 1,000 square feet of lawn each time.

So how much fertilizer do you have to apply to supply a pound of actual nitrogen?

It all depends upon the percentage of nitrogen in your fertilizer. The percent nitrogen is indicated by the first number of three numbers in the fertilizer analysis on the container.

For instance, fertilizer with 20-10-5 analysis contains 20 percent nitrogen by weight. Therefore, you will need to apply five pounds of this fertilizer to provide one pound of actual nitrogen (20 percent times five equals 1). It will take three pounds of a 34-percent material to supply one pound of actual nitrogen and 10 pounds of a 10-percent material.

The second number in the fertilizer analysis represents the percent phosphorus, which generates root growth. The third number is the percent potassium which promotes winter hardiness and stress tolerance.

To prevent streaks from uneven fertilizer application, use a rotary (broadcast) spreader rather than a spreader that drops fertilizer directly onto your lawn. You can apply fertilizer more quickly with a rotary spreader.

Although lawns always need annual applications of nitrogen, phosphorus and potassium, you'll need soil tests to determine your lawn's fertility needs. It's a good idea to take samples for a soil test every three to four years to be sure your lawn is receiving nutrients to meet these needs.

A soil testing service is available to every Kentucky resident through the University of Kentucky College of Agriculture. Our county Extension office has additional information on properly taking soil samples and materials to take these samples.

You'll probably have to mow an extra time or two this fall to keep tall grass from smothering itself out as it goes into the winter. However, this is nothing compared to the number of times you'll need to mow the lawn after spring fertilization. And fall mowing does give you an overall more attractive lawn.
For more information, contact your Hardin County Cooperative Extension Service at 765-4121.