Phosphorus in Lawn Fertilizers
“The Monster in the Middle”
Part 1
By James P. Begick
Begick Nursery and Garden Center, Inc.
“My grass is greener than your grass.”
For many of us, the sight of healthy, pleasantly green lawn is part of a myriad of housekeeping chores.
Some having more importance than others, but it is always on the list. We take care of our lawns for many
reasons, practical and vain. Our lawn is the outdoor carpet, the natural flooring we walk across and the
kids play on. It is the alternative to areas of mud or overgrowth. It gives an order and neatness to our
property. Even if we do not have flowers and trees, if our lawn appears well kept then it implies that we are
as well (just don’t look in my closet).
Because the lawn is a living thing we have to provide for it. A modicum of food and water is necessary to
keep it living and able to fend off diseases and marauding insects, and still stay soft on our feet. How much
care has always been the question. Hence, the fertilizer debate and now pollution issue.
Fertilizers, for the most part, are comprised of three macro-nutrients – nitrogen, phosphorus, and
potassium. The middle number in the fertilizer analysis is phosphorus and is important for root
development, flowering and fruiting, and plant metabolism.
This is the nutrient that has entered the firing line because of its real and perceived negative ecological
effects. It is very true that elevated amounts of phosphorus in our waterway systems significantly increase
algae and other water plant growth and this, in turn, upsets the balance of the water ecosystem. We must
remember, however, that phosphorus comes in different forms and from many sources. Phosphorus
culprits include septic systems (active or inactive), wastewater treatment plant overflows, pet and animal
waste, agricultural erosion, and even atmospheric deposits. And, yes, some of the phosphorus can come
from lawn fertilizers. More on this in future articles.
In late 2007, the Bay County Commission adopted Ordinance #48 that bans lawn fertilizers containing
phosphorus effective January 2009. The words lawn and turf are interchangeable here. Fertilizers used
for home lawns, golf courses, parks, and athletic fields would be ruled by these guidelines. The ban does
not apply to fertilizers for agricultural uses or organic fertilizers. Even so, there are some exceptions to
these turf uses as well. You may use lawn fertilizers containing phosphorus for the following:
Newly established turf or seeding during the first growing season
Turf or lawn areas that soil tests, performed in the past three years by the MSU Extension Service or
other qualified or recognized authority in the area of soil analysis, show are below phosphorus levels
established by the MSU Extension Service. The lawn fertilizer application shall not contain an amount of
phosphorus exceeding the amount and rate of application recommended in the soil test evaluation.
Vegetable or flower gardens, trees or shrubs.
Organic fertilizers listed for lawn use or other agricultural use.
What happens if you don’t comply?
Homeowners and non-professionals will have to pony-up $50.00 for every violation. Professional
applicators will pay $50.00 for the first infraction, $150.00 for the second (within 12 months), and $300.00
for the third with stronger penalties and restitution thereafter.
Who is going to police the ordinance?
The Environmental Health Division of the Bay County Health Department has been charged with the
enforcement of the ordinance.
Homeowners may want to note that they may use any of their previously purchased lawn fertilizers they
may have safely stored at present. They may also purchase and use lawn fertilizers containing
phosphorus through the 2008 season. Our garden center has already made the shift by stocking non-
phosphorus lawn products. It may also be comforting to some that most of the better grade lawn fertilizers
contain very little phosphorus (usually 5% or less by weight) and they have slow release qualities that
drastically reduce the rate that the nutrients are released. The quality levels of established lawns will not
decline because of the new ordinance. Most all of our soils in our area, except for some of the sandy-loam
soils, are rich in phosphorus; so, we don’t anticipate any downside in this area.
There is no argument that we should do whatever we can to re-establish balance in the local ecosystems
and beyond. Certainly, over-applications and irresponsible applications of products always exacerbate the
problems we face. Listed below are a few guidelines we can follow to reduce the amounts of fertilizers and
potential contaminants that enter our waterways.
The steeper the slope, the greater potential for run-off. Lightly water the fertilizer into the grass to
imbed it into the turf to reduce run-off in a hard rain.
Don’t use any more than 1 pound per 1000 square feet of Nitrogen when you fertilize your lawn.
Pay attention to the labels! Twice as much is not twice as good. If you don’t believe this, look at
your waistline.
Leave at least a 10-foot long buffer between your application and any waterway.
Install a barrier fabric as an erosion fence when trying to establish a lawn next to a waterway.
At least 30-35% of nitrogen in the fertilizers should be a coated, slow release product. 12-12-12
type mineral fertilizers have no coatings and release immediately. NOT GOOD!
Keep products from being applied over hard surfaces like driveways, sidewalks, roadways, and
gravel. This will wash into unwanted areas after a rain-storm. Blow off any excess into the lawn areas or
sweep it into containers and discard it.
Make sure compost piles don’t leach into the waterways from rain run-off. Compost contains high
amounts of phosphorus.
Don’t blow lawn clippings into the waterways.
Don’t water every day. Occasional, thorough watering is superior. It will save water in the long run,
and the lawn will be healthier.
Bay County is one of only a few Michigan counties to approve such an ordinance. None of our bordering
counties have adopted any policy thus far and therefore do not have any restriction on the sale or use of
lawn fertilizer products containing phosphorus. Professional organizations like the Michigan Nursery and
Landscape Association (MNLA) and the Michigan Turfgrass Foundation have been working very closely
with Michigan State University to articulate consistent legislative language and better overall protection and
controls. Representatives of these organizations have also served with other groups on the Michigan
Phosphorus Management Advisory Committee by invitation from the Michigan Department of Environmental
Quality. In the next part of the series we will explain some of the views from the Michigan Turfgrass
Foundation (MTF) in their effort to achieve consistent and statewide legislation to reduce phosphorus
levels.