Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001563
11/12/99
Fertilizing Lawns
Fertilizer is essential for good lawn growth. Depending
on the grass grown, 3 to 6 fertilizer applications should
be made during the growing season.
Lawn fertilizers vary in analysis and price. The ideal
analysis for a lawn fertilizer has a 4-1-2 ratio, for
example 20-5-10. Most available lawn fertilizers will not
have this exact ratio but will still give good results.
The price of the fertilizer relates somewhat to the
analysis and the nutrient carriers used on the fertilizer.
Cheap fertilizers are usually water soluble thus have a
high potential to burn the grass. Water soluble
fertilizers will give a response for 4 to 6 weeks. Many
of these fertilizers have disclaimers on the bag stating
they will not burn the grass if the directions are
followed. The directions usually state that the
fertilizer must be watered-in immediately after spreading.
Because these fertilizers are water soluble they become
available in the spring when temperatures are still cool.
More expensive fertilizers are not water soluble, have low
burn potential and give a response for up to 8 weeks.
These fertilizers rely on micro-organisms in the soil to
release the nutrients. Since the micro-organisms are not
active when the soil is cool, the fertilizers will not
become available early in the spring.
Where lawns are watered regularly, especially on sandy
soil, the more expensive types of fertilizers should be
used. Heavy watering will dissolve water soluble
fertilizer and flush it below the root zone of the grass
plants.
Apply fertilizer with a fertilizer spreader. Spreading
fertilizer by hand will always cause some spots to be
over-fertilized and others to have none. When using a
spreader be sure to get complete coverage of the lawn.
Any missed spots will appear quite yellow.
Most lawn fertilizers are packaged so that the right
amount of nutrients are applied per 1000 square feet.
Generally about 1 pound of nitrogen is required at each
fertilization.
Do not fill the spreader when it is sitting on the lawn.
Fertilizer spills are inevitable. Spilling water soluble
fertilizer causes a large dead spot that persists for
weeks.
Begin applying the fertilizer by making "header" strips
around the border of the lawn. Then start at one edge and
go back and forth across the lawn. Make sure each strip
overlaps the previous strip. Turn off the spreader when
the header strip is reached. Do not turn the spreader
while fertilizer is dropping through onto the grass. Such
corners are over-fertilized and the grass could be burned.
Use caution when applying fertilizer combined with
herbicide, especially with broadcast spreaders. These
spreaders can throw the material into flower beds where
the herbicide can injure desirable ornamental plants.
This information is for educational purposes only. References
to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
Extension. Reprinting cannot be used to endorse or advertise
a commercial product or company.
This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
For more information about this data base or its contents please contact
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