Fertilizer: Food for Plants

This article was originally published on milorganite.com

A well-balanced diet provides the nutrients you need to live a healthy life. There are consequences when you’re not getting enough of one nutrient or another. Plants also need a well-balanced, nutritional diet. Their health declines when they’re not getting enough of what they need.

Plants use nutrients they find in the air and soil to grow. Unfortunately, most soils don’t have everything plants need. It’s like looking in your refrigerator and finding only apples. They’re good for you, but they’re not going to provide everything you need to be healthy. It’s similar to plants trying to survive on a diet of only one nutrient.

When plants aren’t getting the balanced diet they need, it’s time to provide a supplement, and fertilizer is the most convenient way to do that.

N-P-K and the numbers on bags of fertilizer explained

The six essential nutrients every plant needs are carbon, hydrogen, and oxygen, which they get from the air, as well as nitrogen (N), phosphorus (P), and potassium (K), which can come from several sources—fertilizer being the most convenient. Those letter abbreviations? Think back to high school chemistry class. Remember the periodic table? They’re the chemical abbreviations for each element.

You’ll find a series of three numbers on every bag of fertilizer. They indicate the percent of each nutrient in the bag, in the same order as N-P-K. The analysis for Milorganite, for example, is 5-4-0, which guarantees there’s 5% nitrogen, 4% phosphorus, and less than one percent potassium in the bag. The analysis is regulated, so rest assured, it’s accurate.

Your lawn has cravings. But for what?

Your balanced meal could include reasonable portions of a protein (steak), starch (baked potato), and vegetable (green beans). (Beer is optional.) Your lawn’s meal would include N-P-K. The question is, now much of each does it need?

You can’t ask your lawn directly what it wants for dinner, but there’s a way to find out: test the soil.

We recommend having your soil tested to find out how much of each nutrient is already in the soil. We also realize most people don’t have their soil tested. We wish they would, but it’s just the way it is.

If we could just convince you that it doesn’t take that much work, will likely cost you less than $20, and you’ll be better able to nurture a beautiful, healthy lawn. Do a search for your state’s county extension offices and “soil testing.” Here’s a resource that can get you started. With the test results in hand, you‘ll know what nutrients your soil lacks to keep your lawn well fed. “Too much of a good thing” is possible with plants, and can be detrimental to your lawn and the environment.

What do the three essential nutrients do for plants?

Here’s a quick rundown of what each of the three essential nutrients does for plants.

Nitrogen (N)

  • Overall plant health, especially above-ground growth.
  • Accelerates growth.
  • Deepens the green color of lawns.
  • Warning: Too much nitrogen makes plants grow more quickly than their roots can support.

Phosphorus (P)

  • Strong root development.
  • Disease resistance.
  • Improved flowering, blooming, fruit growth, and seed production.
  • Warning: Too much phosphorus may leach into groundwater and waterways.

Potassium (K)

  • It’s a “behind-the-scenes” nutrient compared to nitrogen and phosphorus.
  • Necessary for optimum plant growth.
  • Improves water retention.
  • Disease resistance.
  • Protects plants from cold weather.
  • Waring: Too much potassium can inhibit the uptake of other nutrients, such as nitrogen, causing nutrient deficiencies.

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