Nitrogen is a nutrient that turfgrass needs regularly. It’s primarily responsible for blade growth and that rich green color 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 surges in growth 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 or slower rate.

Although green-up is not 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. No matter what you apply, one of the most eco-friendly things you can do is apply no more fertilizer spreader than is needed, apply it correctly and apply it at the right time.

The best place to start is with a soil test. Soil tests found that most home lawns already have adequate amounts of phosphorus since a lawn’s need for phosphorus is lower than thought, due in part to the fact that phosphorus leaches so slowly through the soil.

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 moto mower soil’s acidity level. That’s important not only for good grass growth, but pH affects how fast nutrients break down.