Feeding Your Lawn
Easy Ways to Keep Grass Green and Healthy
Just as the human body requires several vitamins and minerals to
function properly, grass needs about 16 known nutrients for growth and
survival. However, lawns need higher amounts of certain nutrients than
what are naturally present in the soil. This raises three commonly
asked questions about fertilizing:
What type of fertilizer should I use?
When should I fertilize my lawn?
How do I apply fertilizer?
The right food for healthy grass
Nitrogen (N) is, by far, the most abundant element found in plants and
also the one most supplemented. Potassium (K) is second, followed by
phosphorous (P). Each is critical for plant growth, development and
recovery from injury. Excessive or deficient amounts of these
nutrients can lead to unwanted problems, so proper timing, amount and
application techniques are critical.
Vast differences in climate, soil type and grass species make it
impossible for a single fertilizer program to cover all types of
lawns. However, a few generalities can be made surrounding these
questions. (For a more comprehensive guide, check the "Grasses"
Nitrogen comes in two forms: Soluble in water (quickly available to
the plant, or "fast release") and insoluble in water (slowly available
to the plant, or "slow release"). A heavy dose of soluble fertilizer
can sometimes cause unwanted growth spurts and burn the yard.
Conversely, if only slow release nitrogen is used, the yard may
respond more slowly during favorable growing conditions and
unpredictably during times when the lawn is subject to stress.
Therefore, the ideal solution is usually a combination of fast and
slow release nitrogen. This is the idea behind most high quality lawn
fertilizers – meet the daily needs of the plant for an extended time
frame (generally six to 12 weeks). Fertilizer labels typically outline
a guaranteed analysis and break down the types of nitrogen the product
contains. The fertilizer is highly suspect if this information is not
present. Also note that slow release nitrogen products are more
expensive than their quick release counterparts.
Optimal fertilizing time
Simply stated, fertilize when the lawn is actively growing; leave it
alone when it is not. Fertilizer cannot make a lawn grow when
environmental conditions (temperature, water, light) aren't right. The
active growth times for cool season grasses are when temperatures are
between 60 degrees and 80 degrees. For northern climates, this usually
means the most growth occurs in spring and fall with growth slowing in
prolonged hot temperatures. Meanwhile, warm season grasses grow best
when temperatures are above 80 degrees. Therefore, apply fertilizer
during active growth times to build roots and strengthen the plants so
they can survive periods when growth is not as active and there is
greater potential for stress.
Those who live in the Northern U.S. with cool season grasses can
employ the "holiday calendar" fertilizing schedule. As the name
implies, the applications center around four U.S. holidays: Memorial
Day, Fourth of July, Labor Day and Thanksgiving. These dates can be
adjusted based on different geographical regions and climates. Consult
the Yard Doctor Web site's "Yard Care Calendar" for specific
Applying fertilizer like a pro
Fertilizer does not lie about where it has been applied. Those dark
green streaks (that may turn to an ugly brown) are a dead giveaway if
a mistake has been made. The goal of any fertilizer application is to
put down the amount you want, where you want it.
The three most common application methods are liquid sprayer (usually
out of a garden hose), drop spreader, and rotary, or broadcast,
spreader. While a liquid sprayer is quick to use, it is challenging to
achieve an even application. A drop spreader makes it easy to set the
application rate, but the whole yard will need to be covered, just
like a mower. The rotary spreader is by far the most efficient and
accurate device for fertilizer applications because it quickly
distributes the fertilizer to a broad area.
Following label directions is very important when considering how much
fertilizer to use. As a general rule, apply up to one pound of soluble
nitrogen per 1,000 square feet. (Fertilizer products aren't pure
nitrogen, so the actual application of product may be several pounds.)
Because insoluable fertilizer products have less potential to burn the
lawn, up to 2 pounds per 1,000 square feet may be applied.
For best results, follow these tips:
Buy a quality spreader. Inexpensive ones will break down while a good
quality spreader will last a lifetime if cared for properly.
Always wash the spreader after use. Because of its salt properties,
most fertilizer is very corrosive.
Apply fertilizer during ideal conditions. The best conditions combine
freshly mowed grass, no wind and light dew still on the ground. This
will keep the spreader accurate over a smooth ground with its tracks
Know the spreader's capabilities. Most rotary spreaders cover a swatch
6 to 8 feet wide. Keep the wheel tracks at least that far apart on
every pass for best results. For added confidence, set surveyor flags
at the ends of your yard, 8 feet apart, to provide reference points
for an even application.
Avoid skips in the fertilizer by cutting the amount in half and
traveling in two directions. This trick, used by the pros, is the
biggest reason why you don't see streaks caused by too much fertilizer
at golf courses and baseball diamonds.
Start walking before turning on the spreader and shut it off before
you stop walking. This trick will prevent over-applications. Keep the
spreader off when turning around. Instead, make one pass around the
perimeter of the yard to even out the application.
Use the spreader setting guidelines on the fertilizer label. Remember
that there will be variations among various models of spreaders.
Avoid using products with large particles in rotary spreaders.
Products with larger particles are better suited for drop spreaders.
Sufficiently applying fertilizer with a drop spreader requires
overlapping each pass by at least the width of the wheels.
Water the lawn. Improve the fertilizer's efficiency by watering the
lawn soon after an application. Better yet, try applying fertilizer
just before it rains.
Finally, it's easy to be environmentally conscious when using
fertilizer. Try these tips:
Leave your grass clippings on the lawn. This simple gesture saves 1 to
2 pounds of nitrogen per year.
Consider adding a liquid fertilizer application to lawn irrigation
Keep fertilizer out of waterways. Use a drop spreader for accuracy
around sensitive areas.
Clean up spills and sweep up driveways and walks to prevent runoff.
="You make a living by what you get, you make a life by what you give."
-- Winston Churchill