What Kind of Fertilizer is Right for a Lawn?

Everyone wants the most beautiful lawn on the block. And one way to help make yours the envy of the neighborhood is with regular application of fertilizer. Get the most out of your money (and lawn) by knowing what kind of fertilizer is right for a lawn.

Knowing your way around the fertilizer aisle will make keeping your turf looking its best a lot easier, as does knowing your lawn’s needs before you start shopping. Fortunately, it’s easy to cut past marketing on fertilizer bags and assess needs based on the composition of the fertilizer.

Fertilizer Basics

All commercial fertilizers include three basic compounds: nitrogen, phosphorus and potassium. Scientists adjust the composition of a fertilizer to suit different needs by tweaking the ratio of these three ingredients. This composition is spelled out in the fertilizer’s N-P-K rating. Referencing each substance’s chemical symbol, these three numbers indicate the percent of each compound in the fertilizer. A 20-30-15 blend features 20 percent nitrogen, 30 percent phosphorus and 15 percent potassium.

Rather than get caught up in the math and chemistry behind this, it’s easiest just to think of them in terms of ratios.

New Sod

New turf is especially sensitive to fertilizer, and picking the wrong kind can damage it. Select a fertilizer with low or no nitrogen content, and high phosphorus and potassium content. The high amount of phosphorus promotes root growth, while potassium strengthens cell.

Established Lawns

Once your sod has taken root, its needs change, so your fertilizer should, too. Select a fertilizer with a high nitrogen content, and smaller amounts of phosphorus and potassium. Nitrogen promotes thick, rich growth. Nitrogen doesn’t remain in the soil for long periods, and is essential for healthy turf, so frequent reapplication is necessary.

What kind of fertilizer is right for a lawn depends upon how established it is. While it can be tempting to knock out fertilizing and weed control in a single application, many turf managers find they work better independently of each other.