Hints for selecting
an appropriate fertilizer
All fertilizer packages must have three numbers on
them (example: 10-10-10,16-4-8). The numbers rep-
resent the percentages of nitrogen (N), phosphorus
(P) and potassium (K) - in that order - by weight. This
is also referred to as the N-P-K ratio. So, 16-4-8 fertil-
izer is 16 percent nitrogen, 4 percent phosphorus
and 8 percent potassium. While all three are neces-
sary for proper growth, many soils have enough of
certain nutrients. Your soil test will help you under-
stand which nutrients your lawn lacks.
EXAMPLE: Your soil test recommends applying 1
pound actual nitrogen per 1,000 square feet. Say
you have a 40 Ib. bag of 12-4-8. The 12 means the
fertilizer is 12 percent nitrogen by weight. To deter-
mine how many pounds to apply, multiply .12 times
40 Ibs. This equals 4.8 Ibs., the amount of nitrogen in
the bag. Now divide 1, the number of Ibs. per 1,000
sq. ft. you want to spread, by 4.8, the pounds of
nitrogen you have. This gives you .208, or the ratio
for what you want to spread. Now multiply your 40
Ibs. of fertilizer times .208. This gives you 8.3 Ibs. -
the amount of fertilizer to spread over the 1,000 sq.
feet.
Remember, the best fertilizer for your lawn has a
slowly available nitrogen source. "Slow-release"
nitrogen sources are usually stated on the label,
possibly as WIN or water-insoluble nitrogen, sulfur-
coated urea, natural organic nitrogen, etc.
|| HI T.
For dark green turf/ a
good alternative to nitrogen is iron
(periodic use) for "green-up."
Fertilizer application
equipment and methods
Nitrogen fertilizer will generally "green-up" a lawn.
Therefore it is important to apply the fertilizer uni-
formly. Use a drop-type or rotary spreader, and be sure
to overlap adequately. Check the applicator setting often
to be sure you're applying the fertilizer at the proper
rate. Applying fertilizer by hand is not recommended.
for uniform fertilizer
application, apply half in one
direction and the other half in a
perpendicular direction!
These guidelines are basics for having a healthy, attrac-
tive lawn that protects water quality - both nearby and
in the Chesapeake Bay. Your actions do make a differ-
ence. For ideas to make your home landscape more
environmentally sound, contact the Virginia Department
of Conservation and Recreation or Virginia Cooperative
Extension.
1-877-42-WATER
Tech
Tips on
keeping
your
. lawn
i
VIRGINIA POLYTECHNIC INSTITUTE
AND STATE UNIVERSITY
Chesapeake Bay Program
A Watershed Partnership
OCR
Department of Conservation fk Recreation
CONSERVING VIRGINIAS NATURALS RECREATIONAL RESOURCES
The health of Virginia's
waterways begins in
your backyard.
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Tips on keeping your
lawn green... and the
Chesapeake Bay clean
There are 5 million lawns in the Chesapeake Bay
watershed, each with the potential to send a potent
dose of chemicals into local waters and the bay's
fragile ecosystem. These lawns cover Virginia, five
other states, and the District of Columbia.
Improper or excessive lawn fertilization is a signifi-
cant source of nutrient runoff pollution, the most
severe problem facing local waterways and the bay.
Runoff that carries excess nitrogen increases the
growth of algae and reduces water clarity, which
stresses underwater plant and animal life.
Runoff from your property can enter one of more
than 150 creeks, rivers and streams in Virginia that
flow to the bay. The health of Virginia's waterways
begins in your backyard.
You can have a great yard and, at the same time,
help protect local water quality and improve the
Chesapeake Bay. Follow these simple steps, recom-
mended by the Virginia Department of Conservation
and Recreation and Virginia Cooperative Extension.
Growing a greener lawn
Mow high with a sharp blade: 2 to 3 inches for cool-
season grasses and 1 -1 '/2 inches for warm-season
grasses. Don't mow more than 1/3 of the blade at
one time.
Don't mow or fertilize when grass is wet or under
drought stress.
Leave clippings on your lawn - they reduce the
need for nitrogen fertilizer as much as one-third. If
clippings clump, spread them over the lawn with a
rake or pick them up and make compost.
Established plants need little or no water! Save it
for newly planted items, and then let it sink in slowly
and over time.
For dark a green lawn,
select darker grass varieties - they
require less nitrogen and water.
Fertilizer guidelines
Fertilize when grass is actively growing and can take up
the nutrients.
Look for fertilizers with high levels of water insoluble
nitrogen (WIN). It releases fertilizer slowly, and your
lawn makes better use of it.
Never apply more than 1 pound of soluble nitrogen per
1,000 square feet at one time.
Remember, more is not better. Lawn fertilizer is
measured in pounds per 1,000 square feet. To
determine square feet, multiply the length by the width
of the area to be fertilized.
Does my lawn need fertilizer?
The best way to determine whether or not your lawn
needs fertilizer is to test your soil. Information on soil
tests is available through your local Virginia Cooperative
Extension Agent. It's easy and inexpensive. The results
you get back will include recommendations on amounts
of plant nutrients and lime that would benefit your lawn.
Soil tests do not determine nitrogen needs. Nitrogen
should be applied based upon established require-
ments of grass species, seasons of growth and
intended use. (See chart)
What if I don't fertilize?
Your lawn will gradually thin and become more
susceptible to weeds. Proper and timely fertilization can
be good for both your lawn and the environment. There
is less chance of nutrient and soil runoff to surface
waters from a healthy stand of grass than thin grass.
Healthy lawns have less disease, insect and weed
problems, reducing the need for pesticides.
When to fertilize
This depends on the type of grass and the lawn's
appearance - color, density, uniformity - you want.
Summer is best for warm-season grasses, like
Bermudagrass and zoysiagrass. September-
November is best for cool-season grasses like tall fes-
cue, Kentucky bluegrass and perennial ryegrass. If
you don't know what type grass you have, ask your
Extension Agent,or a landscape professional. Never
fertilize when grass is dormant (brown).
Use the following tables to determine nitrogen needs
for established lawns:
Pounds of nitrogen per 1,000 square ft. if the fertilizer is
less than 50 percent WIN
Type of Grass
Month
September
October
Early Nov.
April
May
June
July/August
Yearly IBS
N| 1000 sq.ft.
Tall Fescue
Perennial Rye
1
1
1
0
^^H
0--.5
0
0
2-3.5
Kentucky
Bluegrass
1
1
1
0
0--.5
0
0
3-3.5
Bermudagrass
0
0
0
1
1
1
1
2-4
Zoysiagrass
0
0
0
0
1
0
1
1-2
Pounds of nitrogen per 1,000 sq. ft. if the fertilizer is
more than 50 percent WIN
Type of Grass
Month
August 15
October 1
April
May 15
June
Yearly IBS
NHOOOsq.ft
Tall Fescue
Perennial Rye
1.5
1.5
0
0-1
0
3-4
Kentucky
Bluegrass
1.5
1.5
0
0-1
0
3-4
Bermudagrass
0
0
1.5-2
0
1.5-2
3-4
Zoysiagrass
0
0
1.5-2
0
0
1.5-2
Green areas denote optional or secondary applications
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