The Best Way to Fertilize Your Lawn

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Here are three key questions to consider before fertilizing your lawn.

Is it Plant Food or Soil Food?

Did you ever stop to think about how forests grow so tall, without anyone ever having to spread a drop of fertilizer?

It’s because the leaves, and bark and pine needles all fall to the forest floor and get consumed — or "biodegraded" — by the organisms in the soil. The organisms eat and digest the leaves, then excrete the byproducts, which become the fertilizer that allows the trees to grow.

When we add chemical fertilizers to soil, or spray them on plants, we bypass the natural processes. Organic fertilizers, which come from natural materials including plant and animal byproducts and mined minerals, are intended to enhance the natural processes. These fertilizers, often made from soybeans, alfalfa, corn meal, bone meal etc., are essentially soil foods that must be consumed by soil organisms before they turn plants green. This process of eating, digesting and excreting typically takes longer than applying chemicals to see results, but in the long run the green-up and the growth from organic fertilizers lasts longer and is more sustainable. The organic fertilizers, ultimately, become part of the soil.

Think of it this way: organic fertilizers are like building an annuity. The investment you make this year will continue to pay dividends for years to come. Chemical fertilizers, on the other hand, are like term life insurance. You need to purchase them year after year and the older you get, the more expensive they become.

Does the Product Match the Marketing?

In this era of the Green Movement, some companies are making real and substantive changes to their products to make them more environmentally friendly. Others are simply repacking their wares to make them appear "earth friendly."

This phenomenon of "green washing" is especially prevalent in the gardening world, where clever marketers bend definitions and, at worst, overtly attempt to confuse people. The word "organic" as it relates to fertilizer, means a product should have come from plants, animals or mined minerals. Most companies don't mess with that word on their bags and boxes.

But beware the phrase "organic-based." In virtually all cases, "organic-based" products will actually contain a high percentage of synthetic chemicals. How can you tell for sure? Read the packaging carefully. You can also look for a logo that spells out OMRI, short for Organic Materials Review Institute, which is the national clearing house for organic fertilizer.

How Can 3-1-2 Be Better Than 30-10-20?

Federal regulations require any products sold as fertilizers to print the percentages of N (nitrogen), P (phosphorus) or K (potassium) right on the front of the bag. For the last several decades of gardening dominated by chemical products, those numbers have soared ever higher, with the average chemical lawn "food" now containing 30 percent N, 10 percent P and 20 percent K. That means that in a 40-pound bag, you are actually buying 12 pounds of N, 4 pounds of P and 8 pounds of K.

If you’ve ever thought of switching to organic products, you’ve probably noticed the numbers are far lower, on the order of 90% lower. How can organics add up to be a good deal for you? Consider these factors:

1. Roughly two-thirds of chemical fertilizer never reaches the target plants and instead leaches into surface water, ground water or volatizes into the air we breathe.
2. Excess nutrients can lead to more plant disease and insect pressure, requiring you to spend more money on insecticides, fungicides and herbicides.
3. Organic fertilizers ultimately become part of the soil so that the soil becomes self-sustaining, requiring fewer fertilizer applications in time. Chemical fertilizers must be purchased and applied year after year.

Paul Tukey is the founder of Safelawns.org. See all his Organic Lawn Care Tips.

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