“Eco-Friendly” Fertilizers for a Green Lawn

As “eco-friendly” yard-care practices fast become the new norm, more and more homeowners are looking for options that keep their lawns looking good while minimizing the impact on the environment.

Two ways to do that are by switching to lawn fertilizers that are high in slow-release nitrogen and by switching to new no-phosphorus fertilizers.

Both are aimed at giving lawns only the nutrients they need as they need them, thereby reducing excesses that can run off the property and harm waterways.

Slow-release nitrogen

Nitrogen is a nutrient that turfgrass needs on a regular basis. It’s primarily responsible for blade growth and that rich, green color that most people want.

Older lawn fertilizer nitrogen sources such as urea and ammonium sulfate are water soluble, which makes them readily available to lawn roots. The good news is that they green up lawns quickly and are cheap to produce, but they also can burn lawns when over-applied in warm weather, and cause growth surges that lead to excess mowing and thatch buildup. They also need to be applied four or more times a year to keep a steady supply of nitrogen available. These water soluble fertilizers make up the steps in some 4-step programs and are used by many lawn service companies.

Newer lawn fertilizers use slow- or controlled-release forms of nitrogen. Their breakdown is slowed by pelletizing or encapsulating the nitrogen in membranes or by reformulating the nitrogen so it breaks down at a lower and slower rate.

Although green-up isn’t as immediate with slow-release products and their cost is more, this approach sidesteps growth surges and virtually eliminates the possibility of burning the lawn.

Cutting the phosphorus

A newer environmental concern involves phosphorus, a second main nutrient that turfgrass needs for root and cell development. Up until recently, phosphorus was thought to be needed by lawns in regular amounts, and so lawn fertilizers typically included some in every bag.

Most home lawns already have adequate phosphorus; concerned?
Get a soil test!

But environmental scientists recently found that excess phosphorus was a key cause of algae outbreaks that were clogging waterways. In yards, some phosphorus occurs naturally from the breakdown of plants, but some also comes from the phosphorus applied to lawns in bagged fertilizer.

Soil tests found that most home lawns already have adequate amounts of phosphorus and that a lawn’s need for phosphorus is lower than thought – due in part to the fact that phosphorus leaches so slowly through the soil.

The result is that fertilizers are now available that contain no phosphorus. Greenview’s Fairway Formula fertilizers include zero-phosphorus options for those whose lawns already have adequate phosphorus. Lawns seldom need additional phosphorus in fall, so fall applications are particular good times to consider zero-phosphorus products.

These products also are an option for homeowners in states and municipalities that have begun banning phosphorus-containing fertilizers unless a soil test indicates it’s needed.

When and how much?

No matter what you apply, one of the most eco-friendly things you can do is apply no more fertilizer than is needed, apply it correctly and apply it at the right time.

The best place to start is with a soil test. State Extension services and private labs offer kits that let you mail in soil samples for analysis. The reports give you an accurate reading of what you need and how much of it should be applied. Tests don’t have to be done every year, but they are a good idea every three or four years.

Fertilizing excessively and at the wrong time may cause more harm than good

Remember, more is not better. Not only does excess fertilizer increase the chance of nutrient leaching, it can encourage excess top growth, and make lawns more prone to some diseases, such as leaf spot and brown patch.

On the other hand, under-doing it can lead to a thin lawn. When lawns thin, soil erosion increases. Erosion, in turn, actually increases the amount of nutrients leaving the property — even though you’re applying less.

The goal is to get it just right — enough to encourage optimal growth and a thick stand of grass, but not more than the lawn needs. Without periodic soil tests, you’re left to guess.

Soil tests also will tell you if you need to adjust the soil’s acidity level (its pH). That’s important not only for good grass growth, but pH affects how fast nutrients break down.

The best (and worst) time to apply fertilizer

The best time to apply fertilizer is before you are expecting rain. Otherwise, the fertilizer should be watered in soon after being applied. The idea is to drive the granules into the soil and to begin to dissolve them.

Some of the worst times to fertilize are:

• When a lawn is dormant (cool season grasses go dormant with summer heat, winter freezing and excessive drought or saturation. Warm season grasses thrive in heat and require fertilizer in summer).
• During a drought.
• When the ground is frozen.
• When the ground is saturated or soggy.
• Right before heavy rain is expected.

The best time of year to fertilize cool-season grasses is fall, when growth is slowing and grass blades are transferring sugars to the roots. Homeowners using fertilizers that are highest in slow-release nitrogen (30 percent or more), can grow a good lawn with two fertilizations per year (late spring and early fall). Those using fertilizers with 15 to 29 percent slow-release nitrogen should fertilize in three sessions (late spring, early fall and late fall), while those using mostly fast-release nitrogen (less than 15 percent slow-release) should fertilize four times (mid-spring, early summer, late summer and late fall).

Note: Greenview Fairway Formula Fertilizers are formulated to contain the majority of the nitrogen content in slow release nitrogen.  Greenview's spring fertilizer contains 70% slow release nitrogen.  Greenview's fall fertilizer contains 40% slow release nitrogen.  Greenview's late fall (winterizer) fertilizer contains 90% slow release nitrogen.  The result is better for the grass plant and environment.

Other eco-friendly steps

Some other steps you can take to fertilize in an earth-friendly way:

• Use a drop spreader rather than a spinning-type broadcast spreader. Drop spreaders may take longer, but they’re more accurate at keeping granules where you want them.
• If fertilizer ends up on hard surfaces such as driveways and sidewalks, sweep it up and apply where needed on the lawn or store it for later use.
• Check spreader settings and make sure the application rate matches those on the bag and the rates suggested by your soil test.
• Core-aerate the lawn every fall or two to reduce compaction. That will let fertilizer and water penetrate the soil better.
• Consider planting a native-plant buffer in at least a 15-foot strip between streams and your lawn. This can help any loose soil particles from eroding.