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It's time to prepare for fertilizing the lawn. To begin with, it
is important to know what the numbers on a bag of lawn
fertilizer mean. The bag has numbers like 26-4-7 or 13-13-13.
The first number is the percentage of nitrogen in the product;
the second is the percentage of P2O5, commonly referred to as
phosphorus; and the third is the percentage of K2O, commonly
referred to as potassium or potash. This means that a 10-pound
bag of 13-13-13 would contain 1.3 pounds of nitrogen, 1.3 pounds
of phosphorus and 1.3 pounds of potassium.
It is also
important to know what type of grass you have in your lawn. When
looking at nitrogen application rates, improved bluegrass
varieties (such as A-20 and Delphi) need 4-6 pounds of nitrogen
per 1,000 square feet per year. Common bluegrass varieties (such
as Delta and Park) need 2-4 pounds of nitrogen per year, and
fine-leaf fescues need 1-3 pounds per year per 1,000 square
feet. Nitrogen should be put on at least twice per year, with
ideal times being the first week of May and the first week of
September. Resources vary on recommendations of the amount of
nitrogen that may be safely applied at any one time, with ranges
from 1 to 1.5 pounds per 1,000 square foot maximum. Most current
university information recommends 1 pound maximum per
application.
Phosphorus and potassium should be applied on the basis of
soil testing since these nutrients are not like nitrogen, in
that nitrogen does not remain stable in the soil for long
periods of time. Without a soil analysis, correct applications
are about 1.5-2 pounds of phosphorus and 2.5-3 pounds of
potassium per 1,000 square feet.
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 Boiling this all down to practical terms means that a lawn of
mixed common bluegrass and fine fescue should have about 12 pounds
of 13-13-13 applied twice a year. I realize that you will build up
phosphorus levels somewhat, but not very rapidly. And, the nice
thing is that phosphorus will not be lost. It will remain in the
soil until needed. Another option is to apply most of the phosphorus
and potassium with one application and use one of the high nitrogen
products for the other.
Lawn weed control needs to be done in a couple of weeks if you
are inclined to go after the broadleaf weeds in your grassy setting.
I am mentioning this now because weeds can also be an indicator of
problems. Crabgrass is often an indicator of mowing too short or
watering too frequently. This is often the case when trying to
establish new seed, since there are bare spots and you tend to
moisten frequently. Ground ivy (creeping Charlie) is usually an
indicator of shady conditions or poor drainage. Clovers usually come
in when bare spots are available or there is generally poor
fertility. Knotweed grows in highly compacted areas. Moss grows in
areas with shade, dampness and poor fertility. Some of these
conditions may be controlled to actually control the weed problems
with some cultural changes.
Master Gardener plant sale
The sixth annual Master Gardener plant sale will be Saturday from
9 a.m. until noon or sellout in the Exhibition Building at the Logan
County Fairgrounds. Contrary to popular belief, there have been
plants left at noon the past couple of years. Perennials, annuals,
and houseplants will be available at reasonable prices. Of course,
some of the perennials may look a little bit tough due to the
freeze, but they should grow out just fine.
[Text from file received from
John
Fulton, University of Illinois Extension,
Logan County Unit]
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